Split ImageResourceClient into ResourceClient and ImageResourceObserver [1/2]

third_party/WebKit/Source/core/fetch/ImageResource.h

Index: third_party/WebKit/Source/core/fetch/ImageResource.h
diff --git a/third_party/WebKit/Source/core/fetch/ImageResource.h b/third_party/WebKit/Source/core/fetch/ImageResource.h
index cc4f7aba07f3f8a0c3763d2779538d2ef5877059..e085120358f1d814ad63137b00984ff5f7035b2f 100644
--- a/third_party/WebKit/Source/core/fetch/ImageResource.h
+++ b/third_party/WebKit/Source/core/fetch/ImageResource.h
@@ -35,19 +35,20 @@
 
 namespace blink {
 
-class ImageResourceClient;
 class FetchRequest;
-class ResourceFetcher;
 class FloatSize;
+class ImageResourceObserver;
 class Length;
 class MemoryCache;
+class ResourceClient;
+class ResourceFetcher;
 class SecurityOrigin;
 
 class CORE_EXPORT ImageResource final : public Resource, public ImageObserver, public MultipartImageResourceParser::Client {
     friend class MemoryCache;
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(ImageResource);
 public:
-    using ClientType = ImageResourceClient;
+    using ClientType = ResourceClient;
 
     static PassRefPtrWillBeRawPtr<ImageResource> fetch(FetchRequest&, ResourceFetcher*);
 
@@ -99,10 +100,13 @@ public:
 
     bool isMultipartImage() const { return m_multipartParser; }
 
-    void didAddClient(ResourceClient*) override;
-    void didRemoveClient(ResourceClient*) override;
+    void addObserver(ImageResourceObserver*);
+    void removeObserver(ImageResourceObserver*);
+    bool hasClientsOrObservers() const override { return Resource::hasClientsOrObservers() || !m_observers.isEmpty(); }
+
+    ResourcePriority priorityFromObservers() override;
 
-    void allClientsRemoved() override;
+    void allClientsAndObserversRemoved() override;
 
     void appendData(const char*, size_t) override;
     void error(Resource::Status) override;
@@ -164,6 +168,7 @@ private:
     PersistentWillBeMember<MultipartImageResourceParser> m_multipartParser;
     RefPtr<blink::Image> m_image;
     bool m_hasDevicePixelRatioHeaderValue;
+    HashCountedSet<ImageResourceObserver*> m_observers;
 };
 
 DEFINE_RESOURCE_TYPE_CASTS(Image);