Oilpan: have PageSerializer accurately handle its GCed references.

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 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef PageSerializer_h
 #define PageSerializer_h
 
+#include "platform/heap/Handle.h"
 #include "platform/weborigin/KURL.h"
 #include "platform/weborigin/KURLHash.h"
 #include "wtf/HashMap.h"
 #include "wtf/ListHashSet.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class FontResource;
 class ImageResource;
 class CSSStyleSheet;
 class CSSValue;
 class Document;
 class LocalFrame;
 class Page;
 class RenderObject;
 class Resource;
 class SharedBuffer;
 class StylePropertySet;
 
 struct SerializedResource;
 
 // This class is used to serialize a page contents back to text (typically HTML).
 // It serializes all the page frames and retrieves resources such as images and CSS stylesheets.
-class PageSerializer {
+class PageSerializer final {
+    STACK_ALLOCATED();
 public:
     explicit PageSerializer(Vector<SerializedResource>*);
 
     // Initiates the serialization of the frame's page. All serialized content and retrieved
     // resources are added to the Vector passed to the constructor. The first resource in that
     // vector is the top frame serialized content.
     void serialize(Page*);
 
     KURL urlForBlankFrame(LocalFrame*);
 
 private:
     void serializeFrame(LocalFrame*);
 
     // 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&);
 
     bool shouldAddURL(const KURL&);
 
     void addToResources(Resource *, PassRefPtr<SharedBuffer>, const KURL&);
     void addImageToResources(ImageResource*, RenderObject*, const KURL&);
     void addFontToResources(FontResource*);
 
     void retrieveResourcesForProperties(const StylePropertySet*, Document&);
     void retrieveResourcesForCSSValue(CSSValue*, Document&);
 
     Vector<SerializedResource>* m_resources;
     ListHashSet<KURL> m_resourceURLs;
-    HashMap<LocalFrame*, KURL> m_blankFrameURLs;
+
+    using BlankFrameURLMap = WillBeHeapHashMap<RawPtrWillBeMember<LocalFrame>, KURL>;
+    BlankFrameURLMap m_blankFrameURLs;
     unsigned m_blankFrameCounter;
 };
 
-}
+} // namespace blink
 
-#endif
+#endif // PageSerializer_h