[Not committed] Make image load completion async and remove EventSender from ImageLoader

third_party/WebKit/Source/core/html/HTMLImageLoader.h

Index: third_party/WebKit/Source/core/html/HTMLImageLoader.h
diff --git a/third_party/WebKit/Source/core/html/HTMLImageLoader.h b/third_party/WebKit/Source/core/html/HTMLImageLoader.h
index 59f3bfe6208ab0a7f2ac239b87c524caddc600e1..8a2a93345fb87fd5c4abbbccef97fd3f7761a5a1 100644
--- a/third_party/WebKit/Source/core/html/HTMLImageLoader.h
+++ b/third_party/WebKit/Source/core/html/HTMLImageLoader.h
@@ -36,12 +36,12 @@ public:
     }
     ~HTMLImageLoader() override;
 
+private:
     void dispatchLoadEvent() override;
 
-    void notifyFinished(Resource*) override;
+    void finishInternal(ImageResource*) override;
     String debugName() const override { return "HTMLImageLoader"; }
 
-private:
     explicit HTMLImageLoader(Element*);
     void noImageResourceToLoad() override;
     void ensureFallbackContent();