Phase II Step 3: Reload LoFi/placeholder images via new ImageResource

third_party/WebKit/Source/core/loader/resource/MockImageResourceClient.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MockImageResourceClient_h
 #define MockImageResourceClient_h
 
 #include "core/fetch/MockResourceClient.h"
 #include "core/loader/resource/ImageResource.h"
 #include "core/loader/resource/ImageResourceContent.h"
 #include "core/loader/resource/ImageResourceObserver.h"
 
 namespace blink {
 
+// MockImageResourceClient isn't re-registered to the new ImageResource
+// in LoFi image reloading.

[Nate Chapin, 2016/12/28 00:14:58]

This seems like it's going to trip someone up at some point in the future...

[hiroshige, 2017/01/25 02:01:49]

I replaced MockImageResourceClient with MockImageResourceObserver and makes the
tests observer-based in https://codereview.chromium.org/2607023002, so this
comment no longer applies (and is deleted).

 class MockImageResourceClient final : public MockResourceClient,
                                       public ImageResourceObserver {
  public:
   explicit MockImageResourceClient(ImageResource*);
   ~MockImageResourceClient() override;
 
   void imageNotifyFinished(ImageResourceContent*) override;
   void imageChanged(ImageResourceContent*, const IntRect*) override;
 
   String debugName() const override { return "MockImageResourceClient"; }
 
   bool notifyFinishedCalled() const override;
 
-  void removeAsClient() override;
+  void removeAsClientAndObserver();
   void dispose() override;
 
   int imageChangedCount() const { return m_imageChangedCount; }
   int imageNotifyFinishedCount() const { return m_imageNotifyFinishedCount; }
 
   size_t encodedSizeOnLastImageChanged() const {
     return m_encodedSizeOnLastImageChanged;
   }
   size_t encodedSizeOnImageNotifyFinished() const {
     return m_encodedSizeOnImageNotifyFinished;
   }
 
+  DEFINE_INLINE_VIRTUAL_TRACE() {
+    visitor->trace(m_content);
+    MockResourceClient::trace(visitor);
+  }
+
  private:
   int m_imageChangedCount;
   size_t m_encodedSizeOnLastImageChanged;
   int m_imageNotifyFinishedCount;
   size_t m_encodedSizeOnImageNotifyFinished;
+  Member<ImageResourceContent> m_content;
 };
 
 }  // namespace blink
 
 #endif  // MockImageResourceClient_h