Adjust maximum scroll bounds on FrameView to account for top controls. (Blink-side)

Source/web/WebViewImpl.h

 /*
  * Copyright (C) 2010 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 470 matching lines @@
 
     // Exposed for tests.
     WebVector<WebCompositionUnderline> compositionUnderlines() const;
 
     WebLayerTreeView* layerTreeView() const { return m_layerTreeView; }
 
     bool pinchVirtualViewportEnabled() const;
 
     bool matchesHeuristicsForGpuRasterizationForTesting() const { return m_matchesHeuristicsForGpuRasterization; }
 
+    virtual void setTopControlsLayoutHeight(float) OVERRIDE;
+
 private:
+    void didUpdateTopControls();
     void setTopControlsContentOffset(float);
 
     // TODO(bokan): Remains for legacy pinch. Remove once it's gone. Made private to
     // prevent external usage
     virtual void setPageScaleFactor(float scaleFactor, const WebPoint& origin) OVERRIDE;
 
     float legibleScale() const;
     void refreshPageScaleFactorAfterLayout();
     void resumeTreeViewCommits();
     void setUserAgentPageScaleConstraints(PageScaleConstraints newConstraints);
@@ skipping 211 matching lines @@
     bool m_showFPSCounter;
     bool m_showPaintRects;
     bool m_showDebugBorders;
     bool m_continuousPaintingEnabled;
     bool m_showScrollBottleneckRects;
     WebColor m_baseBackgroundColor;
     WebColor m_backgroundColorOverride;
     float m_zoomFactorOverride;
 
     bool m_userGestureObserved;
+
+    // The top controls offset since the last compositor commit.
     float m_topControlsContentOffset;
+
+    // The top controls offset at the time of the last Resize event. This is the
+    // amount that the viewport was shrunk by to accomodate the top controls.
+    float m_topControlsLayoutHeight;
 };
 
 // We have no ways to check if the specified WebView is an instance of
 // WebViewImpl because WebViewImpl is the only implementation of WebView.
 DEFINE_TYPE_CASTS(WebViewImpl, WebView, webView, true, true);
 
 } // namespace blink
 
 #endif