Bug 1444580: Devirtualize FlushSkinBindings. r=smaug

MozReview-Commit-ID: 556Wpm4QZeM

dom/base/nsDocument.cpp

@@ -6581,7 +6581,7 @@ nsIDocument::MatchMedia(const nsAString& aMediaQueryList,
 }
 
 void
-nsDocument::FlushSkinBindings()
+nsIDocument::FlushSkinBindings()
 {
   BindingManager()->FlushSkinBindings();
 }

dom/base/nsDocument.h

@@ -301,8 +301,6 @@ public:
   virtual void BlockOnload() override;
   virtual void UnblockOnload(bool aFireSync) override;
 
-  virtual void FlushSkinBindings() override;
-
   virtual nsresult InitializeFrameLoader(nsFrameLoader* aLoader) override;
   virtual nsresult FinalizeFrameLoader(nsFrameLoader* aLoader, nsIRunnable* aFinalizer) override;
   virtual void TryCancelFrameLoaderInitialization(nsIDocShell* aShell) override;

dom/base/nsIDocument.h

@@ -2473,7 +2473,7 @@ public:
   /**
    * See FlushSkinBindings on nsBindingManager
    */
-  virtual void FlushSkinBindings() = 0;
+  void FlushSkinBindings();
 
   /**
    * To batch DOMSubtreeModified, document needs to be informed when