Post a microtask to load <img> elements.

Source/core/html/HTMLImageElement.h

Index: Source/core/html/HTMLImageElement.h
diff --git a/Source/core/html/HTMLImageElement.h b/Source/core/html/HTMLImageElement.h
index 5f238cd6619a8ee1a5dc5b95e042cc31e07d70b4..03c3a64f251a3cb1913ca4c8d01f22595c534397 100644
--- a/Source/core/html/HTMLImageElement.h
+++ b/Source/core/html/HTMLImageElement.h
@@ -73,7 +73,7 @@ public:
 
     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; }
 
@@ -123,6 +123,16 @@ private:
 
     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;
@@ -130,6 +140,8 @@ private:
     AtomicString m_bestFitImageURL;
     float m_imageDevicePixelRatio;
     bool m_formWasSetByParser;
+
+    PendingUpdateType m_pendingUpdate;
 };
 
 } //namespace