Don't restart the ImageQualityController timer unless it is already half over.

third_party/WebKit/public/web/WebWidget.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 59 matching lines @@
     // shrink the visible viewport to allow things like the ChromeOS virtual
     // keyboard to overlay over content but allow scrolling it into view.
     virtual void resizeVisualViewport(const WebSize&) { }
 
     // Called to notify the WebWidget of entering/exiting fullscreen mode.
     virtual void didEnterFullScreen() { }
     virtual void didExitFullScreen() { }
 
     // Called to update imperative animation state. This should be called before
     // paint, although the client can rate-limit these calls.
+    // |lastFrameTimeMonotonic| is in seconds.
     virtual void beginFrame(double lastFrameTimeMonotonic) { }
 
     // Called to run through the entire set of document lifecycle phases needed
     // to render a frame of the web widget. This MUST be called before Paint,
     // and it may result in calls to WebWidgetClient::didInvalidateRect.
     virtual void updateAllLifecyclePhases() { }
 
     // Called to paint the rectangular region within the WebWidget
     // onto the specified canvas at (viewPort.x,viewPort.y). You MUST call
     // Layout before calling this method. It is okay to call paint
@@ skipping 154 matching lines @@
     // control what are valid states for top controls and if it should animate.
     virtual void updateTopControlsState(WebTopControlsState constraints, WebTopControlsState current, bool animate) { }
 
 protected:
     ~WebWidget() { }
 };
 
 } // namespace blink
 
 #endif