Bug 656197 part 1. Remove the generic attr preparsing mechanism from BeforeSetAttr and just preparse class attributes directly in the one place that needs to do it. r=smaug

This removes the requirement that BeforeSetAttr comes before AttributeWillChange
(which needs the preparsed new value).

MozReview-Commit-ID: 87C6Mjc7ARh

dom/html/HTMLTextAreaElement.cpp

@@ -985,7 +985,7 @@ HTMLTextAreaElement::UnbindFromTree(bool aDeep, bool aNullParent)
 
 nsresult
 HTMLTextAreaElement::BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
-                                   nsAttrValueOrString* aValue,
+                                   const nsAttrValueOrString* aValue,
                                    bool aNotify)
 {
   if (aNotify && aName == nsGkAtoms::disabled &&