OOPIFs: Deduplicating MHTML parts across frames.

third_party/WebKit/Source/core/page/PageSerializer.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 50 matching lines @@
 struct SerializedResource;
 
 // This class is used to serialize frame's contents back to text (typically HTML).
 // It serializes frame's document and resources such as images and CSS stylesheets.
 // TODO(lukasza): Rename this class to FrameSerializer.
 class CORE_EXPORT PageSerializer final {
     STACK_ALLOCATED();
 public:
     class Delegate {
     public:
-        virtual bool shouldIgnoreAttribute(const Attribute&) = 0;
+        // Controls whether HTML serialization should skip the given attribute.
+        virtual bool shouldIgnoreAttribute(const Attribute&)
+        {
+            return false;
+        }
 
         // Method allowing the Delegate control which URLs are written into the
         // generated html document.
         //
         // When URL of the element needs to be rewritten, this method should
         // return true and populate |rewrittenLink| with a desired value of the
         // html attribute value to be used in place of the original link.
         // (i.e. in place of img.src or iframe.src or object.data).
         //
         // If no link rewriting is desired, this method should return false.
-        virtual bool rewriteLink(const Element&, String& rewrittenLink) = 0;
+        virtual bool rewriteLink(const Element&, String& rewrittenLink)
+        {
+            return false;
+        }
+
+        // Tells whether to skip serialization of a subresource with a given URI.
+        // Used to deduplicate resources across multiple frames.
+        virtual bool shouldSkipResource(const KURL&)
+        {
+            return false;
+        }
     };
 
     // Constructs a serializer that will write output to the given vector of
-    // SerializedResources and use the optional Delegate for controlling some
-    // serialization aspects.  Callers need to ensure that the Delegate stays
+    // SerializedResources and uses the Delegate for controlling some
+    // serialization aspects.  Callers need to ensure that both arguments stay
     // alive until the PageSerializer gets destroyed.
-    PageSerializer(Vector<SerializedResource>&, Delegate*);
+    PageSerializer(Vector<SerializedResource>&, Delegate&);
 
     // Initiates the serialization of the frame. All serialized content and
     // retrieved resources are added to the Vector passed to the constructor.
     // The first resource in that vector is the frame's serialized content.
     // Subsequent resources are images, css, etc.
     void serializeFrame(const LocalFrame&);
 
-    Delegate* delegate();
-
     static String markOfTheWebDeclaration(const KURL&);
 
 private:
     // Serializes the stylesheet back to text and adds it to the resources if URL is not-empty.
     // It also adds any resources included in that stylesheet (including any imported stylesheets and their own resources).
     void serializeCSSStyleSheet(CSSStyleSheet&, const KURL&);
 
     // Serializes the css rule (including any imported stylesheets), adding referenced resources.
     void serializeCSSRule(CSSRule*);
 
     bool shouldAddURL(const KURL&);
 
     void addToResources(Resource *, PassRefPtr<SharedBuffer>, const KURL&);
     void addImageToResources(ImageResource*, const KURL&);
     void addFontToResources(FontResource*);
 
     void retrieveResourcesForProperties(const StylePropertySet*, Document&);
     void retrieveResourcesForCSSValue(CSSValue*, Document&);
 
     Vector<SerializedResource>* m_resources;
     ListHashSet<KURL> m_resourceURLs;
 
-    Delegate* m_delegate;
+    Delegate& m_delegate;
 };
 
 } // namespace blink
 
 #endif // PageSerializer_h