diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 50f5144a7307..29a1ec1936db 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -2683,7 +2683,8 @@ Element::SetAttr(int32_t aNamespaceID, nsAtom* aName,
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (!preparsedAttrValue &&
-      !ParseAttribute(aNamespaceID, aName, aValue, attrValue)) {
+      !ParseAttribute(aNamespaceID, aName, aValue, aSubjectPrincipal,
+                      attrValue)) {
     attrValue.SetTo(aValue);
   }
 
@@ -2903,6 +2904,7 @@ bool
 Element::ParseAttribute(int32_t aNamespaceID,
                         nsAtom* aAttribute,
                         const nsAString& aValue,
+                        nsIPrincipal* aMaybeScriptedPrincipal,
                         nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::lang) {
diff --git a/dom/base/Element.h b/dom/base/Element.h
index 5ad6d0ca55ab..07e7f470d6f3 100644
--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -1565,12 +1565,18 @@ protected:
    * @param aNamespaceID the namespace of the attribute to convert
    * @param aAttribute the attribute to convert
    * @param aValue the string value to convert
+   * @param aMaybeScriptedPrincipal the principal of the script setting the
+   *        attribute, if one can be determined, or null otherwise. As in
+   *        AfterSetAttr, a null value does not guarantee that the attribute was
+   *        not set by a scripted caller, but a non-null value guarantees that
+   *        the attribute was set by a scripted caller with the given principal.
    * @param aResult the nsAttrValue [OUT]
    * @return true if the parsing was successful, false otherwise
    */
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult);
 
   /**
diff --git a/dom/base/nsStyledElement.cpp b/dom/base/nsStyledElement.cpp
index 158994252b03..7c78bfba91a1 100644
--- a/dom/base/nsStyledElement.cpp
+++ b/dom/base/nsStyledElement.cpp
@@ -39,6 +39,7 @@ bool
 nsStyledElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::style && aNamespaceID == kNameSpaceID_None) {
@@ -47,7 +48,7 @@ nsStyledElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsStyledElementBase::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                             aResult);
+                                             aMaybeScriptedPrincipal, aResult);
 }
 
 nsresult
diff --git a/dom/base/nsStyledElement.h b/dom/base/nsStyledElement.h
index 89abe6c6fa46..0d02b08f09ec 100644
--- a/dom/base/nsStyledElement.h
+++ b/dom/base/nsStyledElement.h
@@ -68,7 +68,9 @@ protected:
                            bool aForceInDataDoc);
 
   virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                                const nsAString& aValue, nsAttrValue& aResult) override;
+                                const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
+                                nsAttrValue& aResult) override;
 
   friend class mozilla::dom::Element;
 
diff --git a/dom/html/HTMLBRElement.cpp b/dom/html/HTMLBRElement.cpp
index 4b517843baae..ba2bd5a2e996 100644
--- a/dom/html/HTMLBRElement.cpp
+++ b/dom/html/HTMLBRElement.cpp
@@ -40,6 +40,7 @@ bool
 HTMLBRElement::ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::clear && aNamespaceID == kNameSpaceID_None) {
@@ -47,7 +48,7 @@ HTMLBRElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLBRElement.h b/dom/html/HTMLBRElement.h
index c1c85a6a28bd..ce28ea1e2de5 100644
--- a/dom/html/HTMLBRElement.h
+++ b/dom/html/HTMLBRElement.h
@@ -22,6 +22,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLBodyElement.cpp b/dom/html/HTMLBodyElement.cpp
index c33101254d73..366da713ac53 100644
--- a/dom/html/HTMLBodyElement.cpp
+++ b/dom/html/HTMLBodyElement.cpp
@@ -46,6 +46,7 @@ bool
 HTMLBodyElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -70,7 +71,7 @@ HTMLBodyElement::ParseAttribute(int32_t aNamespaceID,
                                                         aAttribute, aValue,
                                                         aResult) ||
          nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLBodyElement.h b/dom/html/HTMLBodyElement.h
index 475b5088e936..7bcace51e5f1 100644
--- a/dom/html/HTMLBodyElement.h
+++ b/dom/html/HTMLBodyElement.h
@@ -126,6 +126,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLButtonElement.cpp b/dom/html/HTMLButtonElement.cpp
index 4605193a8d30..b1958830fbbd 100644
--- a/dom/html/HTMLButtonElement.cpp
+++ b/dom/html/HTMLButtonElement.cpp
@@ -155,6 +155,7 @@ bool
 HTMLButtonElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -172,7 +173,7 @@ HTMLButtonElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 bool
diff --git a/dom/html/HTMLButtonElement.h b/dom/html/HTMLButtonElement.h
index 4ff8780e0a8b..7dd4d55053a6 100644
--- a/dom/html/HTMLButtonElement.h
+++ b/dom/html/HTMLButtonElement.h
@@ -89,6 +89,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   // nsGenericHTMLElement
diff --git a/dom/html/HTMLCanvasElement.cpp b/dom/html/HTMLCanvasElement.cpp
index e704d9b1a9e6..5ae191137e6a 100644
--- a/dom/html/HTMLCanvasElement.cpp
+++ b/dom/html/HTMLCanvasElement.cpp
@@ -642,6 +642,7 @@ bool
 HTMLCanvasElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None &&
@@ -650,7 +651,7 @@ HTMLCanvasElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 
diff --git a/dom/html/HTMLCanvasElement.h b/dom/html/HTMLCanvasElement.h
index dfc488d50665..c349e4a9c083 100644
--- a/dom/html/HTMLCanvasElement.h
+++ b/dom/html/HTMLCanvasElement.h
@@ -290,6 +290,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute, int32_t aModType) const override;
 
diff --git a/dom/html/HTMLDivElement.cpp b/dom/html/HTMLDivElement.cpp
index 664bc60c9dde..59dc4c52f051 100644
--- a/dom/html/HTMLDivElement.cpp
+++ b/dom/html/HTMLDivElement.cpp
@@ -31,6 +31,7 @@ bool
 HTMLDivElement::ParseAttribute(int32_t aNamespaceID,
                                nsAtom* aAttribute,
                                const nsAString& aValue,
+                               nsIPrincipal* aMaybeScriptedPrincipal,
                                nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -55,7 +56,7 @@ HTMLDivElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLDivElement.h b/dom/html/HTMLDivElement.h
index d8f5247776a8..9d60687327c8 100644
--- a/dom/html/HTMLDivElement.h
+++ b/dom/html/HTMLDivElement.h
@@ -32,6 +32,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLEmbedElement.cpp b/dom/html/HTMLEmbedElement.cpp
index 219a60f874f9..daa97a68ce69 100644
--- a/dom/html/HTMLEmbedElement.cpp
+++ b/dom/html/HTMLEmbedElement.cpp
@@ -221,6 +221,7 @@ bool
 HTMLEmbedElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom *aAttribute,
                                  const nsAString &aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue &aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -233,7 +234,7 @@ HTMLEmbedElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 static void
diff --git a/dom/html/HTMLEmbedElement.h b/dom/html/HTMLEmbedElement.h
index 63bd33fcc003..81349fdec4fa 100644
--- a/dom/html/HTMLEmbedElement.h
+++ b/dom/html/HTMLEmbedElement.h
@@ -48,6 +48,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom *aAttribute,
                               const nsAString &aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue &aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom *aAttribute) const override;
diff --git a/dom/html/HTMLFontElement.cpp b/dom/html/HTMLFontElement.cpp
index 378df4e3f62d..ff4c0f9129ba 100644
--- a/dom/html/HTMLFontElement.cpp
+++ b/dom/html/HTMLFontElement.cpp
@@ -33,6 +33,7 @@ bool
 HTMLFontElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -50,7 +51,7 @@ HTMLFontElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLFontElement.h b/dom/html/HTMLFontElement.h
index 06867bc5f9a8..b8976a5ab42b 100644
--- a/dom/html/HTMLFontElement.h
+++ b/dom/html/HTMLFontElement.h
@@ -48,6 +48,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLFormElement.cpp b/dom/html/HTMLFormElement.cpp
index e81e2f401b69..29f93a044cfe 100644
--- a/dom/html/HTMLFormElement.cpp
+++ b/dom/html/HTMLFormElement.cpp
@@ -279,6 +279,7 @@ bool
 HTMLFormElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -294,7 +295,7 @@ HTMLFormElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 nsresult
diff --git a/dom/html/HTMLFormElement.h b/dom/html/HTMLFormElement.h
index 6012cd55b046..e5e3892776e6 100644
--- a/dom/html/HTMLFormElement.h
+++ b/dom/html/HTMLFormElement.h
@@ -94,6 +94,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsresult GetEventTargetParent(
                      EventChainPreVisitor& aVisitor) override;
diff --git a/dom/html/HTMLFrameElement.cpp b/dom/html/HTMLFrameElement.cpp
index 0b6a638bbbc9..d28e6cde9ffe 100644
--- a/dom/html/HTMLFrameElement.cpp
+++ b/dom/html/HTMLFrameElement.cpp
@@ -33,6 +33,7 @@ bool
 HTMLFrameElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -54,7 +55,7 @@ HTMLFrameElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLFrameElement::ParseAttribute(aNamespaceID, aAttribute,
-                                                   aValue, aResult);
+                                                   aValue, aMaybeScriptedPrincipal, aResult);
 }
 
 JSObject*
diff --git a/dom/html/HTMLFrameElement.h b/dom/html/HTMLFrameElement.h
index 3027860ec91b..6a0304467d46 100644
--- a/dom/html/HTMLFrameElement.h
+++ b/dom/html/HTMLFrameElement.h
@@ -31,6 +31,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
                          bool aPreallocateChildren) const override;
diff --git a/dom/html/HTMLFrameSetElement.cpp b/dom/html/HTMLFrameSetElement.cpp
index 113ec47a18cd..f514eb77f436 100644
--- a/dom/html/HTMLFrameSetElement.cpp
+++ b/dom/html/HTMLFrameSetElement.cpp
@@ -137,6 +137,7 @@ bool
 HTMLFrameSetElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -152,7 +153,7 @@ HTMLFrameSetElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 nsChangeHint
diff --git a/dom/html/HTMLFrameSetElement.h b/dom/html/HTMLFrameSetElement.h
index 2ba3c34b297e..318aa9d0a31a 100644
--- a/dom/html/HTMLFrameSetElement.h
+++ b/dom/html/HTMLFrameSetElement.h
@@ -116,6 +116,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
                                               int32_t aModType) const override;
diff --git a/dom/html/HTMLHRElement.cpp b/dom/html/HTMLHRElement.cpp
index 885e0e713968..1329a02cb7f5 100644
--- a/dom/html/HTMLHRElement.cpp
+++ b/dom/html/HTMLHRElement.cpp
@@ -30,6 +30,7 @@ bool
 HTMLHRElement::ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult)
 {
   static const nsAttrValue::EnumTable kAlignTable[] = {
@@ -55,7 +56,7 @@ HTMLHRElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLHRElement.h b/dom/html/HTMLHRElement.h
index ce75b248b5cc..ab05fea25825 100644
--- a/dom/html/HTMLHRElement.h
+++ b/dom/html/HTMLHRElement.h
@@ -27,6 +27,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLHeadingElement.cpp b/dom/html/HTMLHeadingElement.cpp
index e6a0ecf1033e..03006e533187 100644
--- a/dom/html/HTMLHeadingElement.cpp
+++ b/dom/html/HTMLHeadingElement.cpp
@@ -34,6 +34,7 @@ bool
 HTMLHeadingElement::ParseAttribute(int32_t aNamespaceID,
                                    nsAtom* aAttribute,
                                    const nsAString& aValue,
+                                   nsIPrincipal* aMaybeScriptedPrincipal,
                                    nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::align && aNamespaceID == kNameSpaceID_None) {
@@ -41,7 +42,7 @@ HTMLHeadingElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLHeadingElement.h b/dom/html/HTMLHeadingElement.h
index 56b91c926ade..e1b4779bf39c 100644
--- a/dom/html/HTMLHeadingElement.h
+++ b/dom/html/HTMLHeadingElement.h
@@ -24,6 +24,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLIFrameElement.cpp b/dom/html/HTMLIFrameElement.cpp
index 096cc06186fe..6969e0efb835 100644
--- a/dom/html/HTMLIFrameElement.cpp
+++ b/dom/html/HTMLIFrameElement.cpp
@@ -45,6 +45,7 @@ bool
 HTMLIFrameElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -76,7 +77,9 @@ HTMLIFrameElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLFrameElement::ParseAttribute(aNamespaceID, aAttribute,
-                                                   aValue, aResult);
+                                                   aValue,
+                                                   aMaybeScriptedPrincipal,
+                                                   aResult);
 }
 
 void
diff --git a/dom/html/HTMLIFrameElement.h b/dom/html/HTMLIFrameElement.h
index 6b4bf59f5193..fe6c7cd24f8d 100644
--- a/dom/html/HTMLIFrameElement.h
+++ b/dom/html/HTMLIFrameElement.h
@@ -35,6 +35,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLImageElement.cpp b/dom/html/HTMLImageElement.cpp
index f249759c4a63..e95476c8b8cb 100644
--- a/dom/html/HTMLImageElement.cpp
+++ b/dom/html/HTMLImageElement.cpp
@@ -225,6 +225,7 @@ bool
 HTMLImageElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -241,7 +242,7 @@ HTMLImageElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLImageElement.h b/dom/html/HTMLImageElement.h
index bbebe01d7929..628bd2e9d14b 100644
--- a/dom/html/HTMLImageElement.h
+++ b/dom/html/HTMLImageElement.h
@@ -58,6 +58,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
                                               int32_t aModType) const override;
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index eb151b131e1b..3a4cf9893f91 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -5752,6 +5752,7 @@ bool
 HTMLInputElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   // We can't make these static_asserts because kInputDefaultType and
@@ -5824,7 +5825,7 @@ HTMLInputElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLInputElement.h b/dom/html/HTMLInputElement.h
index 3f3a0ae8a20f..0d85bbf30b13 100644
--- a/dom/html/HTMLInputElement.h
+++ b/dom/html/HTMLInputElement.h
@@ -195,6 +195,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
                                               int32_t aModType) const override;
diff --git a/dom/html/HTMLLIElement.cpp b/dom/html/HTMLLIElement.cpp
index ef23027def75..a3eac53d8394 100644
--- a/dom/html/HTMLLIElement.cpp
+++ b/dom/html/HTMLLIElement.cpp
@@ -49,6 +49,7 @@ bool
 HTMLLIElement::ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -63,7 +64,7 @@ HTMLLIElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLLIElement.h b/dom/html/HTMLLIElement.h
index a38cc278e2bc..118f87c22c19 100644
--- a/dom/html/HTMLLIElement.h
+++ b/dom/html/HTMLLIElement.h
@@ -28,6 +28,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLLegendElement.cpp b/dom/html/HTMLLegendElement.cpp
index 7152e57543f5..a9ef7cf1fccd 100644
--- a/dom/html/HTMLLegendElement.cpp
+++ b/dom/html/HTMLLegendElement.cpp
@@ -38,6 +38,7 @@ bool
 HTMLLegendElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   // this contains center, because IE4 does
@@ -55,7 +56,7 @@ HTMLLegendElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 nsChangeHint
diff --git a/dom/html/HTMLLegendElement.h b/dom/html/HTMLLegendElement.h
index 265212a4496f..70f9d057d2b2 100644
--- a/dom/html/HTMLLegendElement.h
+++ b/dom/html/HTMLLegendElement.h
@@ -39,6 +39,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
                                               int32_t aModType) const override;
diff --git a/dom/html/HTMLLinkElement.cpp b/dom/html/HTMLLinkElement.cpp
index 1469cf49d625..0d2aaf80a7c1 100644
--- a/dom/html/HTMLLinkElement.cpp
+++ b/dom/html/HTMLLinkElement.cpp
@@ -192,6 +192,7 @@ bool
 HTMLLinkElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -217,7 +218,7 @@ HTMLLinkElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLLinkElement.h b/dom/html/HTMLLinkElement.h
index 03c65ab415ee..d9a22012ad1d 100644
--- a/dom/html/HTMLLinkElement.h
+++ b/dom/html/HTMLLinkElement.h
@@ -69,6 +69,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   virtual void GetLinkTarget(nsAString& aTarget) override;
   virtual EventStates IntrinsicState() const override;
diff --git a/dom/html/HTMLMediaElement.cpp b/dom/html/HTMLMediaElement.cpp
index d1df031ef4e7..e03f82092ec7 100644
--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -4459,6 +4459,7 @@ HTMLMediaElement::GetEventTargetParent(EventChainPreVisitor& aVisitor)
 bool HTMLMediaElement::ParseAttribute(int32_t aNamespaceID,
                                       nsAtom* aAttribute,
                                       const nsAString& aValue,
+                                      nsIPrincipal* aMaybeScriptedPrincipal,
                                       nsAttrValue& aResult)
 {
   // Mappings from 'preload' attribute strings to an enumeration.
@@ -4484,7 +4485,7 @@ bool HTMLMediaElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void HTMLMediaElement::DoneCreatingElement()
diff --git a/dom/html/HTMLMediaElement.h b/dom/html/HTMLMediaElement.h
index 7daffdd4aa0f..89555fb19ad9 100644
--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -152,6 +152,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
diff --git a/dom/html/HTMLMenuElement.cpp b/dom/html/HTMLMenuElement.cpp
index 598995817562..18c27347b0d3 100644
--- a/dom/html/HTMLMenuElement.cpp
+++ b/dom/html/HTMLMenuElement.cpp
@@ -128,6 +128,7 @@ bool
 HTMLMenuElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::type) {
@@ -136,7 +137,7 @@ HTMLMenuElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLMenuElement.h b/dom/html/HTMLMenuElement.h
index fce9170eb5e1..6449966e9c3f 100644
--- a/dom/html/HTMLMenuElement.h
+++ b/dom/html/HTMLMenuElement.h
@@ -33,6 +33,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
diff --git a/dom/html/HTMLMenuItemElement.cpp b/dom/html/HTMLMenuItemElement.cpp
index be1f4a66641a..69a535ef31ad 100644
--- a/dom/html/HTMLMenuItemElement.cpp
+++ b/dom/html/HTMLMenuItemElement.cpp
@@ -320,6 +320,7 @@ bool
 HTMLMenuItemElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -335,7 +336,7 @@ HTMLMenuItemElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLMenuItemElement.h b/dom/html/HTMLMenuItemElement.h
index b2cc887ad008..096137ae7ef7 100644
--- a/dom/html/HTMLMenuItemElement.h
+++ b/dom/html/HTMLMenuItemElement.h
@@ -43,6 +43,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   virtual void DoneCreatingElement() override;
diff --git a/dom/html/HTMLMeterElement.cpp b/dom/html/HTMLMeterElement.cpp
index 4608d2b7b331..c85157f55dda 100644
--- a/dom/html/HTMLMeterElement.cpp
+++ b/dom/html/HTMLMeterElement.cpp
@@ -40,8 +40,11 @@ HTMLMeterElement::IntrinsicState() const
 }
 
 bool
-HTMLMeterElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                                 const nsAString& aValue, nsAttrValue& aResult)
+HTMLMeterElement::ParseAttribute(int32_t aNamespaceID,
+                                 nsAtom* aAttribute,
+                                 const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
+                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::value || aAttribute == nsGkAtoms::max ||
@@ -52,7 +55,9 @@ HTMLMeterElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute,
-                                                  aValue, aResult);
+                                              aValue,
+                                              aMaybeScriptedPrincipal,
+                                              aResult);
 }
 
 /*
diff --git a/dom/html/HTMLMeterElement.h b/dom/html/HTMLMeterElement.h
index 0eca31f986dc..fc5ed08597dc 100644
--- a/dom/html/HTMLMeterElement.h
+++ b/dom/html/HTMLMeterElement.h
@@ -27,8 +27,10 @@ public:
   nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult,
                  bool aPreallocateChildren) const override;
 
-  bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                      const nsAString& aValue, nsAttrValue& aResult) override;
+  virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                              const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
+                              nsAttrValue& aResult) override;
 
   // WebIDL
 
diff --git a/dom/html/HTMLObjectElement.cpp b/dom/html/HTMLObjectElement.cpp
index ae551b3dd473..d16b8d81a888 100644
--- a/dom/html/HTMLObjectElement.cpp
+++ b/dom/html/HTMLObjectElement.cpp
@@ -453,6 +453,7 @@ bool
 HTMLObjectElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom *aAttribute,
                                   const nsAString &aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue &aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -465,7 +466,7 @@ HTMLObjectElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLFormElement::ParseAttribute(aNamespaceID, aAttribute,
-                                                  aValue, aResult);
+                                                  aValue, aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLObjectElement.h b/dom/html/HTMLObjectElement.h
index 10e2cddfd162..2a77f3c28a2b 100644
--- a/dom/html/HTMLObjectElement.h
+++ b/dom/html/HTMLObjectElement.h
@@ -70,6 +70,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom *aAttribute,
                                 const nsAString &aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue &aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom *aAttribute) const override;
diff --git a/dom/html/HTMLOutputElement.cpp b/dom/html/HTMLOutputElement.cpp
index 4a0a3d2285ef..eedf2d1bff6d 100644
--- a/dom/html/HTMLOutputElement.cpp
+++ b/dom/html/HTMLOutputElement.cpp
@@ -70,8 +70,11 @@ HTMLOutputElement::SubmitNamesValues(HTMLFormSubmission* aFormSubmission)
 }
 
 bool
-HTMLOutputElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                                  const nsAString& aValue, nsAttrValue& aResult)
+HTMLOutputElement::ParseAttribute(int32_t aNamespaceID,
+                                  nsAtom* aAttribute,
+                                  const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
+                                  nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::_for) {
@@ -81,7 +84,9 @@ HTMLOutputElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
   }
 
   return nsGenericHTMLFormElement::ParseAttribute(aNamespaceID, aAttribute,
-                                                  aValue, aResult);
+                                                  aValue,
+                                                  aMaybeScriptedPrincipal,
+                                                  aResult);
 }
 
 void
diff --git a/dom/html/HTMLOutputElement.h b/dom/html/HTMLOutputElement.h
index 70d7ada06013..e8cabce8627d 100644
--- a/dom/html/HTMLOutputElement.h
+++ b/dom/html/HTMLOutputElement.h
@@ -39,8 +39,10 @@ public:
   nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult,
                  bool aPreallocateChildren) const override;
 
-  bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                        const nsAString& aValue, nsAttrValue& aResult) override;
+  virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                              const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
+                              nsAttrValue& aResult) override;
 
   virtual void DoneAddingChildren(bool aHaveNotified) override;
 
diff --git a/dom/html/HTMLParagraphElement.cpp b/dom/html/HTMLParagraphElement.cpp
index 3d0ef00ba2cb..31d8992759f4 100644
--- a/dom/html/HTMLParagraphElement.cpp
+++ b/dom/html/HTMLParagraphElement.cpp
@@ -29,6 +29,7 @@ bool
 HTMLParagraphElement::ParseAttribute(int32_t aNamespaceID,
                                      nsAtom* aAttribute,
                                      const nsAString& aValue,
+                                     nsIPrincipal* aMaybeScriptedPrincipal,
                                      nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::align && aNamespaceID == kNameSpaceID_None) {
@@ -36,7 +37,7 @@ HTMLParagraphElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLParagraphElement.h b/dom/html/HTMLParagraphElement.h
index ddea1b477ee9..d330cbaa448c 100644
--- a/dom/html/HTMLParagraphElement.h
+++ b/dom/html/HTMLParagraphElement.h
@@ -28,6 +28,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLPreElement.cpp b/dom/html/HTMLPreElement.cpp
index 0d1eded0309c..96f30146536a 100644
--- a/dom/html/HTMLPreElement.cpp
+++ b/dom/html/HTMLPreElement.cpp
@@ -30,6 +30,7 @@ bool
 HTMLPreElement::ParseAttribute(int32_t aNamespaceID,
                                nsAtom* aAttribute,
                                const nsAString& aValue,
+                               nsIPrincipal* aMaybeScriptedPrincipal,
                                nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -39,7 +40,7 @@ HTMLPreElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLPreElement.h b/dom/html/HTMLPreElement.h
index 719dc1b0e74f..c832e42db220 100644
--- a/dom/html/HTMLPreElement.h
+++ b/dom/html/HTMLPreElement.h
@@ -28,6 +28,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
diff --git a/dom/html/HTMLProgressElement.cpp b/dom/html/HTMLProgressElement.cpp
index eb5b56112068..cb357619a85f 100644
--- a/dom/html/HTMLProgressElement.cpp
+++ b/dom/html/HTMLProgressElement.cpp
@@ -45,8 +45,11 @@ HTMLProgressElement::IntrinsicState() const
 }
 
 bool
-HTMLProgressElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                                    const nsAString& aValue, nsAttrValue& aResult)
+HTMLProgressElement::ParseAttribute(int32_t aNamespaceID,
+                                    nsAtom* aAttribute,
+                                    const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
+                                    nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
     if (aAttribute == nsGkAtoms::value || aAttribute == nsGkAtoms::max) {
@@ -55,7 +58,9 @@ HTMLProgressElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute,
-                                              aValue, aResult);
+                                              aValue,
+                                              aMaybeScriptedPrincipal,
+                                              aResult);
 }
 
 double
diff --git a/dom/html/HTMLProgressElement.h b/dom/html/HTMLProgressElement.h
index 37ef382d8db5..f1de7347e5d5 100644
--- a/dom/html/HTMLProgressElement.h
+++ b/dom/html/HTMLProgressElement.h
@@ -26,8 +26,10 @@ public:
   nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo, nsINode** aResult,
                  bool aPreallocateChildren) const override;
 
-  bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                        const nsAString& aValue, nsAttrValue& aResult) override;
+  virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                              const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
+                              nsAttrValue& aResult) override;
 
   // WebIDL
   double Value() const;
diff --git a/dom/html/HTMLScriptElement.cpp b/dom/html/HTMLScriptElement.cpp
index ccb7accd74d5..dca545917b41 100644
--- a/dom/html/HTMLScriptElement.cpp
+++ b/dom/html/HTMLScriptElement.cpp
@@ -73,6 +73,7 @@ bool
 HTMLScriptElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -88,7 +89,7 @@ HTMLScriptElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 nsresult
diff --git a/dom/html/HTMLScriptElement.h b/dom/html/HTMLScriptElement.h
index a0a5ffaf915c..877bccb85b0b 100644
--- a/dom/html/HTMLScriptElement.h
+++ b/dom/html/HTMLScriptElement.h
@@ -45,6 +45,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
diff --git a/dom/html/HTMLSelectElement.cpp b/dom/html/HTMLSelectElement.cpp
index 4bf0ec3519c0..151be03f638b 100644
--- a/dom/html/HTMLSelectElement.cpp
+++ b/dom/html/HTMLSelectElement.cpp
@@ -1257,6 +1257,7 @@ bool
 HTMLSelectElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (kNameSpaceID_None == aNamespaceID) {
@@ -1268,7 +1269,7 @@ HTMLSelectElement::ParseAttribute(int32_t aNamespaceID,
     }
   }
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLSelectElement.h b/dom/html/HTMLSelectElement.h
index 782df8bbae8c..2d7a19a03092 100644
--- a/dom/html/HTMLSelectElement.h
+++ b/dom/html/HTMLSelectElement.h
@@ -384,6 +384,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
diff --git a/dom/html/HTMLSharedElement.cpp b/dom/html/HTMLSharedElement.cpp
index ff7902b83aaa..6b5d5194f3b2 100644
--- a/dom/html/HTMLSharedElement.cpp
+++ b/dom/html/HTMLSharedElement.cpp
@@ -60,6 +60,7 @@ bool
 HTMLSharedElement::ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None &&
@@ -73,7 +74,7 @@ HTMLSharedElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 static void
diff --git a/dom/html/HTMLSharedElement.h b/dom/html/HTMLSharedElement.h
index daff95083c39..ac39214148b8 100644
--- a/dom/html/HTMLSharedElement.h
+++ b/dom/html/HTMLSharedElement.h
@@ -33,6 +33,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
diff --git a/dom/html/HTMLSharedListElement.cpp b/dom/html/HTMLSharedListElement.cpp
index 1f87523c70ba..c8ed8e8e0662 100644
--- a/dom/html/HTMLSharedListElement.cpp
+++ b/dom/html/HTMLSharedListElement.cpp
@@ -59,6 +59,7 @@ bool
 HTMLSharedListElement::ParseAttribute(int32_t aNamespaceID,
                                       nsAtom* aAttribute,
                                       const nsAString& aValue,
+                                      nsIPrincipal* aMaybeScriptedPrincipal,
                                       nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -75,7 +76,7 @@ HTMLSharedListElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLSharedListElement.h b/dom/html/HTMLSharedListElement.h
index 02d31cb08a6d..3fa79f4fc111 100644
--- a/dom/html/HTMLSharedListElement.h
+++ b/dom/html/HTMLSharedListElement.h
@@ -28,6 +28,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTableCaptionElement.cpp b/dom/html/HTMLTableCaptionElement.cpp
index b4e407747f91..81879881bb58 100644
--- a/dom/html/HTMLTableCaptionElement.cpp
+++ b/dom/html/HTMLTableCaptionElement.cpp
@@ -40,6 +40,7 @@ bool
 HTMLTableCaptionElement::ParseAttribute(int32_t aNamespaceID,
                                         nsAtom* aAttribute,
                                         const nsAString& aValue,
+                                        nsIPrincipal* aMaybeScriptedPrincipal,
                                         nsAttrValue& aResult)
 {
   if (aAttribute == nsGkAtoms::align && aNamespaceID == kNameSpaceID_None) {
@@ -47,7 +48,7 @@ HTMLTableCaptionElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTableCaptionElement.h b/dom/html/HTMLTableCaptionElement.h
index 1d4b7d3ccaca..06278b2f62da 100644
--- a/dom/html/HTMLTableCaptionElement.h
+++ b/dom/html/HTMLTableCaptionElement.h
@@ -33,6 +33,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTableCellElement.cpp b/dom/html/HTMLTableCellElement.cpp
index b3d10267e985..cc4201b764e5 100644
--- a/dom/html/HTMLTableCellElement.cpp
+++ b/dom/html/HTMLTableCellElement.cpp
@@ -147,6 +147,7 @@ bool
 HTMLTableCellElement::ParseAttribute(int32_t aNamespaceID,
                                      nsAtom* aAttribute,
                                      const nsAString& aValue,
+                                     nsIPrincipal* aMaybeScriptedPrincipal,
                                      nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -193,7 +194,7 @@ HTMLTableCellElement::ParseAttribute(int32_t aNamespaceID,
                                                         aAttribute, aValue,
                                                         aResult) ||
          nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTableCellElement.h b/dom/html/HTMLTableCellElement.h
index 0294b52f0b40..813a2934656f 100644
--- a/dom/html/HTMLTableCellElement.h
+++ b/dom/html/HTMLTableCellElement.h
@@ -139,6 +139,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD WalkContentStyleRules(nsRuleWalker* aRuleWalker) override;
diff --git a/dom/html/HTMLTableColElement.cpp b/dom/html/HTMLTableColElement.cpp
index fdfa60912a3e..4d0031497912 100644
--- a/dom/html/HTMLTableColElement.cpp
+++ b/dom/html/HTMLTableColElement.cpp
@@ -35,6 +35,7 @@ bool
 HTMLTableColElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -59,7 +60,7 @@ HTMLTableColElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTableColElement.h b/dom/html/HTMLTableColElement.h
index f248bdb3555a..ed7c02faef86 100644
--- a/dom/html/HTMLTableColElement.h
+++ b/dom/html/HTMLTableColElement.h
@@ -74,6 +74,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTableElement.cpp b/dom/html/HTMLTableElement.cpp
index 621687ab61bd..7fecda481b80 100644
--- a/dom/html/HTMLTableElement.cpp
+++ b/dom/html/HTMLTableElement.cpp
@@ -891,6 +891,7 @@ bool
 HTMLTableElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   /* ignore summary, just a string */
@@ -932,7 +933,7 @@ HTMLTableElement::ParseAttribute(int32_t aNamespaceID,
                                                         aAttribute, aValue,
                                                         aResult) ||
          nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 
diff --git a/dom/html/HTMLTableElement.h b/dom/html/HTMLTableElement.h
index b3a3f7892940..51c1588ada89 100644
--- a/dom/html/HTMLTableElement.h
+++ b/dom/html/HTMLTableElement.h
@@ -185,6 +185,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTableRowElement.cpp b/dom/html/HTMLTableRowElement.cpp
index 197588720da3..e1dfebfda31e 100644
--- a/dom/html/HTMLTableRowElement.cpp
+++ b/dom/html/HTMLTableRowElement.cpp
@@ -221,6 +221,7 @@ bool
 HTMLTableRowElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   /*
@@ -254,7 +255,7 @@ HTMLTableRowElement::ParseAttribute(int32_t aNamespaceID,
                                                         aAttribute, aValue,
                                                         aResult) ||
          nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTableRowElement.h b/dom/html/HTMLTableRowElement.h
index fea3fb1175f7..09d24f8004f7 100644
--- a/dom/html/HTMLTableRowElement.h
+++ b/dom/html/HTMLTableRowElement.h
@@ -81,6 +81,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTableSectionElement.cpp b/dom/html/HTMLTableSectionElement.cpp
index 724ada852df1..945c41fe52f2 100644
--- a/dom/html/HTMLTableSectionElement.cpp
+++ b/dom/html/HTMLTableSectionElement.cpp
@@ -130,6 +130,7 @@ bool
 HTMLTableSectionElement::ParseAttribute(int32_t aNamespaceID,
                                         nsAtom* aAttribute,
                                         const nsAString& aValue,
+                                        nsIPrincipal* aMaybeScriptedPrincipal,
                                         nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -157,7 +158,7 @@ HTMLTableSectionElement::ParseAttribute(int32_t aNamespaceID,
                                                         aAttribute, aValue,
                                                         aResult) ||
          nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTableSectionElement.h b/dom/html/HTMLTableSectionElement.h
index 1e260a1ba449..cb73ac7249bc 100644
--- a/dom/html/HTMLTableSectionElement.h
+++ b/dom/html/HTMLTableSectionElement.h
@@ -66,6 +66,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/html/HTMLTextAreaElement.cpp b/dom/html/HTMLTextAreaElement.cpp
index ca6385c928fc..4b47ee5e05d6 100644
--- a/dom/html/HTMLTextAreaElement.cpp
+++ b/dom/html/HTMLTextAreaElement.cpp
@@ -425,6 +425,7 @@ bool
 HTMLTextAreaElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -443,7 +444,7 @@ HTMLTextAreaElement::ParseAttribute(int32_t aNamespaceID,
     }
   }
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                              aResult);
+                                              aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLTextAreaElement.h b/dom/html/HTMLTextAreaElement.h
index e468b69330bb..1f7d9ae1e605 100644
--- a/dom/html/HTMLTextAreaElement.h
+++ b/dom/html/HTMLTextAreaElement.h
@@ -125,6 +125,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
   virtual nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
diff --git a/dom/html/HTMLTrackElement.cpp b/dom/html/HTMLTrackElement.cpp
index ee1a5deb7726..08a6c0f334d3 100644
--- a/dom/html/HTMLTrackElement.cpp
+++ b/dom/html/HTMLTrackElement.cpp
@@ -218,6 +218,7 @@ bool
 HTMLTrackElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::kind) {
@@ -230,6 +231,7 @@ HTMLTrackElement::ParseAttribute(int32_t aNamespaceID,
   return nsGenericHTMLElement::ParseAttribute(aNamespaceID,
                                               aAttribute,
                                               aValue,
+                                              aMaybeScriptedPrincipal,
                                               aResult);
 }
 
diff --git a/dom/html/HTMLTrackElement.h b/dom/html/HTMLTrackElement.h
index a440ba817755..615df846706d 100644
--- a/dom/html/HTMLTrackElement.h
+++ b/dom/html/HTMLTrackElement.h
@@ -97,6 +97,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   // Override BindToTree() so that we can trigger a load when we become
diff --git a/dom/html/HTMLVideoElement.cpp b/dom/html/HTMLVideoElement.cpp
index ecc99c99bd1e..f586cece6d8c 100644
--- a/dom/html/HTMLVideoElement.cpp
+++ b/dom/html/HTMLVideoElement.cpp
@@ -86,6 +86,7 @@ bool
 HTMLVideoElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
    if (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height) {
@@ -93,7 +94,7 @@ HTMLVideoElement::ParseAttribute(int32_t aNamespaceID,
    }
 
    return HTMLMediaElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                           aResult);
+                                           aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/html/HTMLVideoElement.h b/dom/html/HTMLVideoElement.h
index 1f922a37a6cd..3ba157ed6a95 100644
--- a/dom/html/HTMLVideoElement.h
+++ b/dom/html/HTMLVideoElement.h
@@ -38,6 +38,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
 
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index ba1886796010..a0737711c99e 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -927,6 +927,7 @@ bool
 nsGenericHTMLElement::ParseAttribute(int32_t aNamespaceID,
                                      nsAtom* aAttribute,
                                      const nsAString& aValue,
+                                     nsIPrincipal* aMaybeScriptedPrincipal,
                                      nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -964,7 +965,8 @@ nsGenericHTMLElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsGenericHTMLElementBase::ParseAttribute(aNamespaceID, aAttribute,
-                                                  aValue, aResult);
+                                                  aValue, aMaybeScriptedPrincipal,
+                                                  aResult);
 }
 
 bool
diff --git a/dom/html/nsGenericHTMLElement.h b/dom/html/nsGenericHTMLElement.h
index 1c5043bf72e2..456654903247 100644
--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -344,6 +344,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   bool ParseBackgroundAttribute(int32_t aNamespaceID,
diff --git a/dom/mathml/nsMathMLElement.cpp b/dom/mathml/nsMathMLElement.cpp
index b61af114c566..591c510d3ddc 100644
--- a/dom/mathml/nsMathMLElement.cpp
+++ b/dom/mathml/nsMathMLElement.cpp
@@ -145,6 +145,7 @@ bool
 nsMathMLElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   MOZ_ASSERT(IsMathMLElement());
@@ -177,7 +178,9 @@ nsMathMLElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsMathMLElementBase::ParseAttribute(aNamespaceID, aAttribute,
-                                             aValue, aResult);
+                                             aValue,
+                                             aMaybeScriptedPrincipal,
+                                             aResult);
 }
 
 static Element::MappedAttributeEntry sMtableStyles[] = {
diff --git a/dom/mathml/nsMathMLElement.h b/dom/mathml/nsMathMLElement.h
index 8b26a25c7f6f..5616e704ff19 100644
--- a/dom/mathml/nsMathMLElement.h
+++ b/dom/mathml/nsMathMLElement.h
@@ -51,6 +51,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
diff --git a/dom/svg/SVGAnimateTransformElement.cpp b/dom/svg/SVGAnimateTransformElement.cpp
index ee6718746e48..686816cabc55 100644
--- a/dom/svg/SVGAnimateTransformElement.cpp
+++ b/dom/svg/SVGAnimateTransformElement.cpp
@@ -30,6 +30,7 @@ bool
 SVGAnimateTransformElement::ParseAttribute(int32_t aNamespaceID,
                                            nsAtom* aAttribute,
                                            const nsAString& aValue,
+                                           nsIPrincipal* aMaybeScriptedPrincipal,
                                            nsAttrValue& aResult)
 {
   // 'type' is an <animateTransform>-specific attribute, and we'll handle it
@@ -49,6 +50,7 @@ SVGAnimateTransformElement::ParseAttribute(int32_t aNamespaceID,
 
   return SVGAnimationElement::ParseAttribute(aNamespaceID,
                                              aAttribute, aValue,
+                                             aMaybeScriptedPrincipal,
                                              aResult);
 }
 
diff --git a/dom/svg/SVGAnimateTransformElement.h b/dom/svg/SVGAnimateTransformElement.h
index 4d9f25b15088..ec281af919cc 100644
--- a/dom/svg/SVGAnimateTransformElement.h
+++ b/dom/svg/SVGAnimateTransformElement.h
@@ -35,10 +35,11 @@ public:
                          bool aPreallocateChildren) const override;
 
   // Element specializations
-  bool ParseAttribute(int32_t aNamespaceID,
-                        nsAtom* aAttribute,
-                        const nsAString& aValue,
-                        nsAttrValue& aResult) override;
+  virtual bool ParseAttribute(int32_t aNamespaceID,
+                              nsAtom* aAttribute,
+                              const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
+                              nsAttrValue& aResult) override;
 
   // SVGAnimationElement
   virtual nsSMILAnimationFunction& AnimationFunction() override;
diff --git a/dom/svg/SVGAnimationElement.cpp b/dom/svg/SVGAnimationElement.cpp
index fa65a38e9497..d7db9f1bae86 100644
--- a/dom/svg/SVGAnimationElement.cpp
+++ b/dom/svg/SVGAnimationElement.cpp
@@ -244,6 +244,7 @@ bool
 SVGAnimationElement::ParseAttribute(int32_t aNamespaceID,
                                     nsAtom* aAttribute,
                                     const nsAString& aValue,
+                                    nsIPrincipal* aMaybeScriptedPrincipal,
                                     nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None) {
@@ -278,7 +279,9 @@ SVGAnimationElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return SVGAnimationElementBase::ParseAttribute(aNamespaceID, aAttribute,
-                                                 aValue, aResult);
+                                                 aValue,
+                                                 aMaybeScriptedPrincipal,
+                                                 aResult);
 }
 
 nsresult
diff --git a/dom/svg/SVGAnimationElement.h b/dom/svg/SVGAnimationElement.h
index d4fb8d80ee42..1a1405b56531 100644
--- a/dom/svg/SVGAnimationElement.h
+++ b/dom/svg/SVGAnimationElement.h
@@ -57,6 +57,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
   virtual nsresult AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
                                 const nsAttrValue* aValue,
diff --git a/dom/svg/SVGMPathElement.cpp b/dom/svg/SVGMPathElement.cpp
index 034e1b28b11d..134f4fda453b 100644
--- a/dom/svg/SVGMPathElement.cpp
+++ b/dom/svg/SVGMPathElement.cpp
@@ -119,11 +119,14 @@ bool
 SVGMPathElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   bool returnVal =
     SVGMPathElementBase::ParseAttribute(aNamespaceID, aAttribute,
-                                          aValue, aResult);
+                                          aValue,
+                                          aMaybeScriptedPrincipal,
+                                          aResult);
   if ((aNamespaceID == kNameSpaceID_XLink ||
        aNamespaceID == kNameSpaceID_None ) &&
       aAttribute == nsGkAtoms::href &&
diff --git a/dom/svg/SVGMPathElement.h b/dom/svg/SVGMPathElement.h
index 177b70cd57d0..2e1de868c17b 100644
--- a/dom/svg/SVGMPathElement.h
+++ b/dom/svg/SVGMPathElement.h
@@ -55,6 +55,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   // Public helper method: If our xlink:href attribute links to a <path>
diff --git a/dom/svg/SVGMarkerElement.cpp b/dom/svg/SVGMarkerElement.cpp
index 6421e9b7b881..7abc0f795017 100644
--- a/dom/svg/SVGMarkerElement.cpp
+++ b/dom/svg/SVGMarkerElement.cpp
@@ -211,6 +211,7 @@ SVGMarkerElement::IsAttributeMapped(const nsAtom* name) const
 bool
 SVGMarkerElement::ParseAttribute(int32_t aNameSpaceID, nsAtom* aName,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::orient) {
@@ -230,7 +231,9 @@ SVGMarkerElement::ParseAttribute(int32_t aNameSpaceID, nsAtom* aName,
     mOrientType.SetBaseValue(SVG_MARKER_ORIENT_ANGLE);
   }
   return SVGMarkerElementBase::ParseAttribute(aNameSpaceID, aName,
-                                              aValue, aResult);
+                                              aValue,
+                                              aMaybeScriptedPrincipal,
+                                              aResult);
 }
 
 nsresult
diff --git a/dom/svg/SVGMarkerElement.h b/dom/svg/SVGMarkerElement.h
index 24ec11f79c6a..c0a0a4a24473 100644
--- a/dom/svg/SVGMarkerElement.h
+++ b/dom/svg/SVGMarkerElement.h
@@ -151,6 +151,7 @@ protected:
 
   virtual bool ParseAttribute(int32_t aNameSpaceID, nsAtom* aName,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult) override;
 
   void SetParentCoordCtxProvider(SVGViewportElement *aContext);
diff --git a/dom/svg/SVGScriptElement.cpp b/dom/svg/SVGScriptElement.cpp
index 01a78e816cd0..b8915c0aee6f 100644
--- a/dom/svg/SVGScriptElement.cpp
+++ b/dom/svg/SVGScriptElement.cpp
@@ -252,6 +252,7 @@ bool
 SVGScriptElement::ParseAttribute(int32_t aNamespaceID,
                                  nsAtom* aAttribute,
                                  const nsAString& aValue,
+                                 nsIPrincipal* aMaybeScriptedPrincipal,
                                  nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None &&
@@ -261,7 +262,9 @@ SVGScriptElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return SVGScriptElementBase::ParseAttribute(aNamespaceID, aAttribute,
-                                              aValue, aResult);
+                                              aValue,
+                                              aMaybeScriptedPrincipal,
+                                              aResult);
 }
 
 CORSMode
diff --git a/dom/svg/SVGScriptElement.h b/dom/svg/SVGScriptElement.h
index a84a57245fda..0dac960a6ad4 100644
--- a/dom/svg/SVGScriptElement.h
+++ b/dom/svg/SVGScriptElement.h
@@ -62,6 +62,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
diff --git a/dom/svg/SVGStyleElement.cpp b/dom/svg/SVGStyleElement.cpp
index 94e08d0d2897..54c21bcf43a6 100644
--- a/dom/svg/SVGStyleElement.cpp
+++ b/dom/svg/SVGStyleElement.cpp
@@ -135,6 +135,7 @@ bool
 SVGStyleElement::ParseAttribute(int32_t aNamespaceID,
                                 nsAtom* aAttribute,
                                 const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
                                 nsAttrValue& aResult)
 {
   if (aNamespaceID == kNameSpaceID_None &&
@@ -144,7 +145,7 @@ SVGStyleElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return SVGStyleElementBase::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                             aResult);
+                                             aMaybeScriptedPrincipal, aResult);
 }
 
 //----------------------------------------------------------------------
diff --git a/dom/svg/SVGStyleElement.h b/dom/svg/SVGStyleElement.h
index d14a9f3fbe11..e3495966ef3f 100644
--- a/dom/svg/SVGStyleElement.h
+++ b/dom/svg/SVGStyleElement.h
@@ -54,6 +54,7 @@ public:
   virtual bool ParseAttribute(int32_t aNamespaceID,
                               nsAtom* aAttribute,
                               const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
                               nsAttrValue& aResult) override;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult,
diff --git a/dom/svg/nsSVGElement.cpp b/dom/svg/nsSVGElement.cpp
index 3fc236be30b1..6fbef9ec4445 100644
--- a/dom/svg/nsSVGElement.cpp
+++ b/dom/svg/nsSVGElement.cpp
@@ -341,6 +341,7 @@ bool
 nsSVGElement::ParseAttribute(int32_t aNamespaceID,
                              nsAtom* aAttribute,
                              const nsAString& aValue,
+                             nsIPrincipal* aMaybeScriptedPrincipal,
                              nsAttrValue& aResult)
 {
   nsresult rv = NS_OK;
@@ -673,7 +674,7 @@ nsSVGElement::ParseAttribute(int32_t aNamespaceID,
   }
 
   return nsSVGElementBase::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                          aResult);
+                                          aMaybeScriptedPrincipal, aResult);
 }
 
 void
diff --git a/dom/svg/nsSVGElement.h b/dom/svg/nsSVGElement.h
index 0ce2dde9fa32..16478314c977 100644
--- a/dom/svg/nsSVGElement.h
+++ b/dom/svg/nsSVGElement.h
@@ -355,7 +355,9 @@ protected:
                                 nsIPrincipal* aSubjectPrincipal,
                                 bool aNotify) override;
   virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
-                                const nsAString& aValue, nsAttrValue& aResult) override;
+                                const nsAString& aValue,
+                                nsIPrincipal* aMaybeScriptedPrincipal,
+                                nsAttrValue& aResult) override;
   static nsresult ReportAttributeParseFailure(nsIDocument* aDocument,
                                               nsAtom* aAttribute,
                                               const nsAString& aValue);
diff --git a/dom/xul/nsXULElement.cpp b/dom/xul/nsXULElement.cpp
index a8a5bc6f9063..a509e7c8d31c 100644
--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -1161,11 +1161,12 @@ bool
 nsXULElement::ParseAttribute(int32_t aNamespaceID,
                              nsAtom* aAttribute,
                              const nsAString& aValue,
+                             nsIPrincipal* aMaybeScriptedPrincipal,
                              nsAttrValue& aResult)
 {
     // Parse into a nsAttrValue
     if (!nsStyledElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
-                                         aResult)) {
+                                         aMaybeScriptedPrincipal, aResult)) {
         // Fall back to parsing as atom for short values
         aResult.ParseStringOrAtom(aValue);
     }
diff --git a/dom/xul/nsXULElement.h b/dom/xul/nsXULElement.h
index 6f7c82f25a09..b65fe0ddad64 100644
--- a/dom/xul/nsXULElement.h
+++ b/dom/xul/nsXULElement.h
@@ -759,6 +759,7 @@ protected:
     virtual bool ParseAttribute(int32_t aNamespaceID,
                                   nsAtom* aAttribute,
                                   const nsAString& aValue,
+                                  nsIPrincipal* aMaybeScriptedPrincipal,
                                   nsAttrValue& aResult) override;
 
     virtual mozilla::EventListenerManager*