Normalize top controls offset to (0, 1), 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 497 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;
+    virtual void setTopControlsHeight(float height, bool topControlsShrinkLayoutSize) override;
 
     virtual void forceNextWebGLContextCreationToFail() override;
 
     IntSize mainFrameSize();
 
 private:
     void didUpdateTopControls();
     void setTopControlsContentOffset(float);
 
     // TODO(bokan): Remains for legacy pinch. Remove once it's gone. Made private to
@@ skipping 224 matching lines @@
     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;
+    float m_topControlsHeight;
+    // If this is true, then the viewport was shrunk by the top controls height
+    // as of the last Resize event.

[bokan, 2015/02/06 08:25:23]

It'd be more clear to say here (and in WebView.h) that the "WebView was shrunk
by the top controls...". 

[aelias_OOO_until_Jul13, 2015/02/06 20:32:37]

Done.

+    bool m_topControlsShrinkLayoutSize;
+
+    // If true, then top controls is normalized between 0 and 1; if false,
+    // then it's an absolute value.
+    // TODO(aelias): Delete this after Blink roll.
+    bool m_topControlsOffsetIsNormalized;
 };
 
 DEFINE_TYPE_CASTS(WebViewImpl, WebWidget, widget, widget->isWebView(), widget.isWebView());
 // 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