Allow eviction of ImageBitmaps that are created from ImageElements.

Source/core/loader/ImageLoader.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 97 matching lines @@
     // Only consider updating the protection ref-count of the Element immediately before returning
     // from this function as doing so might result in the destruction of this ImageLoader.
     updatedHasPendingEvent();
 }
 
 void ImageLoader::setImageWithoutConsideringPendingLoadEvent(CachedImage* newImage)
 {
     ASSERT(m_failedLoadURL.isEmpty());
     CachedImage* oldImage = m_image.get();
     if (newImage != oldImage) {
+        sourceImageChanged();
         m_image = newImage;
         if (m_hasPendingBeforeLoadEvent) {
             beforeLoadEventSender().cancelEvent(this);
             m_hasPendingBeforeLoadEvent = false;
         }
         if (m_hasPendingLoadEvent) {
             loadEventSender().cancelEvent(this);
             m_hasPendingLoadEvent = false;
         }
         if (m_hasPendingErrorEvent) {
@@ skipping 55 matching lines @@
             m_failedLoadURL = attr;
             m_hasPendingErrorEvent = true;
             errorEventSender().dispatchEventSoon(this);
         } else
             clearFailedLoadURL();
     } else if (!attr.isNull()) {
         // Fire an error event if the url is empty.
         m_hasPendingErrorEvent = true;
         errorEventSender().dispatchEventSoon(this);
     }
-    
+
     CachedImage* oldImage = m_image.get();
     if (newImage != oldImage) {
+        sourceImageChanged();
+
         if (m_hasPendingBeforeLoadEvent) {
             beforeLoadEventSender().cancelEvent(this);
             m_hasPendingBeforeLoadEvent = false;
         }
         if (m_hasPendingLoadEvent) {
             loadEventSender().cancelEvent(this);
             m_hasPendingLoadEvent = false;
         }
 
         // Cancel error events that belong to the previous load, which is now cancelled by changing the src attribute.
@@ skipping 231 matching lines @@
 {
     errorEventSender().dispatchPendingEvents();
 }
 
 void ImageLoader::elementDidMoveToNewDocument()
 {
     clearFailedLoadURL();
     setImage(0);
 }
 
+void ImageLoader::sourceImageChanged()
+{
+    HashSet<ImageLoaderClient*>::iterator end = m_clients.end();
+    for (HashSet<ImageLoaderClient*>::iterator it = m_clients.begin(); it != end; ++it) {
+        ImageLoaderClient* handle = *it;
+        handle->notifyImageSourceChanged();
+    }
+}
+
 inline void ImageLoader::clearFailedLoadURL()
 {
     m_failedLoadURL = AtomicString();
 }
 
 }