Implement top controls show/hide functionality for main thread scrolling

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 14 matching lines @@
 
 #ifndef WebLayerTreeView_h
 #define WebLayerTreeView_h
 
 #include "WebColor.h"
 #include "WebCommon.h"
 #include "WebFloatPoint.h"
 #include "WebNonCopyable.h"
 #include "WebPrivateOwnPtr.h"
 #include "WebSize.h"
+#include "public/web/WebTopControlsState.h"
 
 class SkBitmap;
 
 namespace blink {
 
 class WebCompositeAndReadbackAsyncCallback;
 class WebLayer;
 struct WebPoint;
 struct WebSelectionBound;
+class WebWidget;
 
 class WebLayerTreeView {
 public:
     virtual ~WebLayerTreeView() { }
 
     // Initialization and lifecycle --------------------------------------
 
     // Sets the root of the tree. The root is set by way of the constructor.
     virtual void setRootLayer(const WebLayer&) = 0;
     virtual void clearRootLayer() = 0;
@@ skipping 25 matching lines @@
     // 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 amount that the top controls are showing, from 0 (hidden) to 1
     // (fully shown).
     virtual void setTopControlsShownRatio(float) { }
 
+    // Update top controls permitted and current states
+    virtual void updateTopControlsState(WebTopControlsState constraints, WebTopControlsState current, bool animate) { }
+
+    // If this is set to true, then the embedder shrunk the WebView size by the top

[aelias_OOO_until_Jul13, 2015/02/13 02:03:17]

Please update the comment to say that this means Blink shrunk the viewport clip
layers by the top control height, as that's the relevant meaning from the point
of view of CC.

[majidvp, 2015/02/18 21:03:57]

Done.

+    // controls height.
+    virtual void setTopControlsShrinkBlinkSize(bool shrink) { }
+
+    // Set top controls height
+    virtual void setTopControlsHeight(float height) { }
+
     // 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.
     virtual void didStopFlinging() { }
@@ 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