Made Blink aware of top controls offset (Blink-side)

public/platform/WebLayerTreeView.h

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 75 matching lines @@
     // Sets the current page scale factor and minimum / maximum limits. Both limits are initially 1 (no page scale allowed).
     virtual void setPageScaleFactorAndLimits(float pageScaleFactor, float minimum, float maximum) = 0;
 
     // Starts an animation of the page scale to a target scale factor and scroll offset.
     // If useAnchor is true, destination is a point on the screen that will remain fixed for the duration of the animation.
     // If useAnchor is false, destination is the final top-left scroll position.
     virtual void startPageScaleAnimation(const WebPoint& destination, bool useAnchor, float newPageScale, double durationSec) = 0;
 
     virtual void heuristicsForGpuRasterizationUpdated(bool) { }
 
+    // Sets the offset from the top of the screen that the contents are displaced by due to top controls showing.
+    virtual void setTopControlsContentOffset(float) { }
+
 
     // Flow control and scheduling ---------------------------------------
 
     // Indicates that an animation needs to be updated.
     virtual void setNeedsAnimate() = 0;
 
     // Indicates whether a commit is pending.
     virtual bool commitRequested() const = 0;
 
     // Relays the end of a fling animation.
@@ skipping 42 matching lines @@
     // Toggles continuous painting
     virtual void setContinuousPaintingEnabled(bool) { }
 
     // Toggles scroll bottleneck rects on the HUD layer
     virtual void setShowScrollBottleneckRects(bool) { }
 };
 
 } // namespace blink
 
 #endif // WebLayerTreeView_h