Bug 229925 - Do not dispatch event to label target if interactive content is found between the event target and the label. r=smaug

dom/html/HTMLButtonElement.h

@@ -36,6 +36,12 @@ public:
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLButtonElement, button)
 
+  // Element
+  virtual bool IsInteractiveHTMLContent() const MOZ_OVERRIDE
+  {
+    return true;
+  }
+
   // nsIDOMHTMLButtonElement
   NS_DECL_NSIDOMHTMLBUTTONELEMENT