Post a microtask to load <img> elements.

Source/core/html/HTMLImageElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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 55 matching lines @@
     KURL src() const;
     void setSrc(const String&);
 
     void setWidth(int);
 
     int x() const;
     int y() const;
 
     bool complete() const;
 
-    bool hasPendingActivity() const { return m_imageLoader.hasPendingActivity(); }
+    bool hasPendingActivity() const { return m_imageLoader.hasPendingActivity() || hasPendingUpdate(); }
 
     virtual bool canContainRangeEndPoint() const OVERRIDE { return false; }
 
     void addClient(ImageLoaderClient* client) { m_imageLoader.addClient(client); }
     void removeClient(ImageLoaderClient* client) { m_imageLoader.removeClient(client); }
 
     virtual const AtomicString imageSourceURL() const OVERRIDE;
 
     virtual HTMLFormElement* formOwner() const OVERRIDE;
     void formRemovedFromTree(const Node& formRoot);
@@ skipping 29 matching lines @@
 
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
     virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual bool shouldRegisterAsNamedItem() const OVERRIDE { return true; }
     virtual bool shouldRegisterAsExtraNamedItem() const OVERRIDE { return true; }
     virtual bool isInteractiveContent() const OVERRIDE;
     virtual Image* imageContents() OVERRIDE;
 
     void resetFormOwner();
 
+    enum PendingUpdateType {
+        PendingUpdateNone,
+        PendingUpdateIgnoreError,
+        PendingUpdateNormal
+    };
+    void enqueueUpdate(PendingUpdateType);
+    bool hasPendingUpdate() const { return m_pendingUpdate != PendingUpdateNone; }
+    void cancelPendingUpdate();
+    static void processUpdateFromElementQueue();
+
     HTMLImageLoader m_imageLoader;
     // m_form should be a strong reference in Oilpan.
     WeakPtr<HTMLFormElement> m_form;
     CompositeOperator m_compositeOperator;
     AtomicString m_bestFitImageURL;
     float m_imageDevicePixelRatio;
     bool m_formWasSetByParser;
+
+    PendingUpdateType m_pendingUpdate;
 };
 
 } //namespace
 
 #endif