Implement top controls show/hide functionality for main thread scrolling

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 55 matching lines @@
 
 namespace blink {
 
 class DataObject;
 class Frame;
 class FullscreenController;
 class InputMethodContext;
 class LinkHighlight;
 class PopupContainer;
 class LayerCompositor;
+class TopControls;
 class UserGestureToken;
 class WebActiveGestureAnimation;
 class WebDevToolsAgentImpl;
 class WebLayerTreeView;
 class WebLocalFrameImpl;
 class WebImage;
 class WebPagePopupImpl;
 class WebPlugin;
 class WebSettingsImpl;
 
@@ skipping 424 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 setTopControlsHeight(float height, bool topControlsShrinkLayoutSize) override;
+    virtual void updateTopControlsState(WebTopControlsState constraint, WebTopControlsState current, bool animate) override;
+
+    TopControls& topControls();
+    // Called anytime top controls layout height or content offset have changed.
+    void didUpdateTopControls();
 
     virtual void forceNextWebGLContextCreationToFail() override;
 
     IntSize mainFrameSize();
 
 private:
-    void didUpdateTopControls();
     void setTopControlsShownRatio(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;
     void setPageScaleFactorAndLocation(float, const FloatPoint&);
 
     void scrollAndRescaleViewports(float scaleFactor, const IntPoint& mainFrameOrigin, const FloatPoint& pinchViewportOrigin);
 
     IntRect visibleRectInDocument() const;
 
     float legibleScale() const;
@@ skipping 210 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 shown amount (normalized from 0 to 1) since the last
-    // compositor commit.
-    float m_topControlsShownRatio;
-
-    float m_topControlsHeight;
-    // If this is true, then the embedder shrunk the WebView size by the top
-    // controls height.
-    bool m_topControlsShrinkLayoutSize;
 };
 
 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