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

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 23 matching lines @@
 
 namespace blink {
 
 class IncrementLoadEventDelayCount;
 class FetchRequest;
 class Document;
 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);
 public:
     explicit ImageLoader(Element*);
     ~ImageLoader() override;
 
     DECLARE_TRACE();
 
     enum UpdateFromElementBehavior {
@@ skipping 15 matching lines @@
         DoNotBypassMainWorldCSP
     };
 
     void updateFromElement(UpdateFromElementBehavior = UpdateNormal, ReferrerPolicy = ReferrerPolicyDefault);
 
     void elementDidMoveToNewDocument();
 
     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(); }
     void setImage(ImageResource*); // Cancels pending load events, and doesn't dispatch new ones.
 
     void setLoadingImageDocument() { m_loadingImageDocument = true; }
 
     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*);
+    bool getImageAnimationPolicy(ImageAnimationPolicy&) final;
 
-    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);
 
     void timerFired(Timer<ImageLoader>*);
 
     KURL imageSourceToKURL(AtomicString) const;
 
     // Used to determine whether to immediately initiate the load
     // or to schedule a microtask.
     bool shouldLoadImmediately(const KURL&) const;
 
     // For Oilpan, we must run dispose() as a prefinalizer and call
     // m_image->removeClient(this) (and more.) Otherwise, the ImageResource can invoke
     // didAddClient() for the ImageLoader that is about to die in the current
     // lazy sweeping, and the didAddClient() can access on-heap objects that
     // have already been finalized in the current lazy sweeping.
     void dispose();
 
     RawPtrWillBeMember<Element> m_element;
     RefPtrWillBeMember<ImageResource> m_image;
     // FIXME: Oilpan: We might be able to remove this Persistent hack when
     // ImageResourceClient is traceable.
     GC_PLUGIN_IGNORE("http://crbug.com/383741")
     RefPtrWillBePersistent<Element> m_keepAlive;
 
     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;
     bool m_suppressErrorEvents : 1;
 };
 
 } // namespace blink
 
 #endif