mac: Only let two-finger-scrolling trigger history if web doesn't swallow gesture

chrome/browser/renderer_host/render_widget_host_view_views.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_VIEWS_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_VIEWS_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 74 matching lines @@
                                 const gfx::Point& end) OVERRIDE;
   virtual void ShowingContextMenu(bool showing) OVERRIDE;
   virtual BackingStore* AllocBackingStore(const gfx::Size& size) OVERRIDE;
   virtual void SetBackground(const SkBitmap& background) OVERRIDE;
 #if defined(TOOLKIT_USES_GTK)
   virtual void CreatePluginContainer(gfx::PluginWindowHandle id) OVERRIDE;
   virtual void DestroyPluginContainer(gfx::PluginWindowHandle id) OVERRIDE;
 #endif
   virtual void SetVisuallyDeemphasized(const SkColor* color,
                                        bool animate) OVERRIDE;
+  virtual void UnhandledWheelEvent(
+      const WebKit::WebMouseWheelEvent& event) OVERRIDE;
+  virtual void SetHasHorizontalScrollbar(
+      bool has_horizontal_scrollbar) OVERRIDE;
+  virtual void SetScrollOffsetPinning(
+      bool is_pinned_to_left, bool is_pinned_to_right) OVERRIDE;
 #if defined(TOOLKIT_USES_GTK)
   virtual void AcceleratedCompositingActivated(bool activated) OVERRIDE;
 #endif
 #if defined(OS_WIN)
   virtual void WillWmDestroy() OVERRIDE;
   virtual void ShowCompositorHostWindow(bool show) OVERRIDE;
 #endif
   virtual gfx::PluginWindowHandle GetCompositingSurface() OVERRIDE;
 
   // Overridden from views::TouchSelectionClientView.
@@ skipping 154 matching lines @@
 
 #if defined(TOUCH_UI)
   std::map<uint64, scoped_refptr<AcceleratedSurfaceContainerTouch> >
       accelerated_surface_containers_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewViews);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_VIEWS_H_