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

third_party/WebKit/Source/platform/loader/fetch/Resource.h

Index: third_party/WebKit/Source/platform/loader/fetch/Resource.h
diff --git a/third_party/WebKit/Source/platform/loader/fetch/Resource.h b/third_party/WebKit/Source/platform/loader/fetch/Resource.h
index cbd4c0f77aad190928e26e693641f6334982e325..dc3e485ffc6f1fea615032122c6d901a7e407b48 100644
--- a/third_party/WebKit/Source/platform/loader/fetch/Resource.h
+++ b/third_party/WebKit/Source/platform/loader/fetch/Resource.h
@@ -331,8 +331,14 @@ class PLATFORM_EXPORT Resource : public GarbageCollectedFinalized<Resource>,
   // If this Resource is ImageResource and has the Lo-Fi response headers or is
   // a placeholder, reload the full original image with the Lo-Fi state set to
   // off and optionally bypassing the cache.
-  virtual void reloadIfLoFiOrPlaceholderImage(ResourceFetcher*,
-                                              ReloadLoFiOrPlaceholderPolicy) {}
+  // If reloading is started, this method returns a new Resource that is used
+  // for reloading, and |this| should be no longer used.
+  // Otherwise, this method returns nullptr.
+  virtual Resource* reloadIfLoFiOrPlaceholderImage(
+      ResourceFetcher*,
+      ReloadLoFiOrPlaceholderPolicy) {
+    return nullptr;
+  }
 
   static const char* resourceTypeToString(
       Type,
@@ -390,10 +396,6 @@ class PLATFORM_EXPORT Resource : public GarbageCollectedFinalized<Resource>,
     return m_clients;
   }
 
-  void setCachePolicyBypassingCache();
-  void setPreviewsStateNoTransform();
-  void clearRangeRequestHeader();
-
   SharedBuffer* data() const { return m_data.get(); }
   void clearData();