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

third_party/WebKit/Source/core/loader/ImageLoader.h

Index: third_party/WebKit/Source/core/loader/ImageLoader.h
diff --git a/third_party/WebKit/Source/core/loader/ImageLoader.h b/third_party/WebKit/Source/core/loader/ImageLoader.h
index abb6414f84a8288205bf85839ff01ec0ab02031b..040fd3e61f1e9ba4d600efa35c90654ed45eb3d2 100644
--- a/third_party/WebKit/Source/core/loader/ImageLoader.h
+++ b/third_party/WebKit/Source/core/loader/ImageLoader.h
@@ -41,9 +41,6 @@ class Element;
 class ImageLoader;
 class LayoutImageResource;
 
-template<typename T> class EventSender;
-using ImageEventSender = EventSender<ImageLoader>;
-
 class CORE_EXPORT ImageLoader : public NoBaseWillBeGarbageCollectedFinalized<ImageLoader>, public ResourceClient, public ImageResourceObserver {
     WILL_BE_USING_PRE_FINALIZER(ImageLoader, dispose);
     USING_FAST_MALLOC_WILL_BE_REMOVED(ImageLoader);
@@ -79,7 +76,7 @@ public:
     Element* element() const { return m_element; }
     bool imageComplete() const
     {
-        return m_imageComplete && !m_pendingTask;
+        return m_imageComplete && !m_pendingMicrotask;
     }
 
     ImageResource* image() const { return m_image.get(); }
@@ -89,43 +86,47 @@ public:
 
     bool hasPendingActivity() const
     {
-        return m_hasPendingLoadEvent || m_hasPendingErrorEvent || m_pendingTask;
+        return m_hasPendingLoadEvent || hasPendingError() || m_pendingMicrotask;
     }
 
     bool hasPendingError() const
     {
-        return m_hasPendingErrorEvent;
+        return m_loadDelayCounterForError;
     }
 
-    void dispatchPendingEvent(ImageEventSender*);
-
-    static void dispatchPendingLoadEvents();
-    static void dispatchPendingErrorEvents();
-
     bool getImageAnimationPolicy(ImageAnimationPolicy&) final;
+
 protected:
-    void notifyFinished(Resource*) override;
+    virtual void finishInternal(ImageResource*) { }
 
 private:
     class Task;
 
+    void notifyFinished(Resource*) final;
+
     // Called from the task or from updateFromElement to initiate the load.
     void doUpdateFromElement(BypassMainWorldBehavior, UpdateFromElementBehavior, ReferrerPolicy = ReferrerPolicyDefault);
 
-    virtual void dispatchLoadEvent() = 0;
     virtual void noImageResourceToLoad() { }
 
     void updatedHasPendingEvent();
 
-    void dispatchPendingLoadEvent();
-    void dispatchPendingErrorEvent();
+    void scheduleFinish();
+    void cancelPendingFinish();
+    void finish();
+
+    virtual void dispatchLoadEvent() = 0;
+
+    void scheduleErrorEvent();
+    void cancelPendingErrorEvent();
+    void dispatchErrorEvent();
+    void dispatchErrorEventWithoutUpdatedHasPendingEvent();
 
     LayoutImageResource* layoutImageResource();
     void updateLayoutObject();
 
     void setImageWithoutConsideringPendingLoadEvent(ImageResource*);
     void clearFailedLoadURL();
-    void dispatchErrorEvent();
     void crossSiteOrCSPViolationOccurred(AtomicString);
     void enqueueImageLoadingMicroTask(UpdateFromElementBehavior, ReferrerPolicy);
 
@@ -153,10 +154,16 @@ private:
 
     Timer<ImageLoader> m_derefElementTimer;
     AtomicString m_failedLoadURL;
-    WeakPtr<Task> m_pendingTask; // owned by Microtask
-    OwnPtr<IncrementLoadEventDelayCount> m_loadDelayCounter;
+
+    WeakPtr<Task> m_pendingMicrotask; // owned by Microtask
+    OwnPtr<CancellableTaskFactory> m_finishTask;
+    OwnPtr<CancellableTaskFactory> m_dispatchErrorEventTask;
+
+    OwnPtr<IncrementLoadEventDelayCount> m_loadDelayCounterForMicrotask;
+    OwnPtr<IncrementLoadEventDelayCount> m_loadDelayCounterForFinish;
+    OwnPtr<IncrementLoadEventDelayCount> m_loadDelayCounterForError;
+
     bool m_hasPendingLoadEvent : 1;
-    bool m_hasPendingErrorEvent : 1;
     bool m_imageComplete : 1;
     bool m_loadingImageDocument : 1;
     bool m_elementIsProtected : 1;