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

content/browser/renderer_host/render_widget_host_view.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 CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_H_
 #pragma once
 
 #if defined(OS_MACOSX)
 #include <OpenGL/OpenGL.h>
 #endif
 
 #include <string>
 #include <vector>
 
 #include "base/process_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupType.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/base/range/range.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/surface/transport_dib.h"
 
 namespace gfx {
 class Rect;
 class Size;
@@ skipping 260 matching lines @@
   virtual gfx::PluginWindowHandle GetCompositingSurface() = 0;
 
   // Toggles visual muting of the render view area. This is on when a
   // constrained window is showing, for example. |color| is the shade of
   // the overlay that covers the render view. If |animate| is true, the overlay
   // gradually fades in; otherwise it takes effect immediately. To remove the
   // fade effect, pass a NULL value for |color|. In this case, |animate| is
   // ignored.
   virtual void SetVisuallyDeemphasized(const SkColor* color, bool animate) = 0;
 
+  virtual void UnhandledWheelEvent(const WebKit::WebMouseWheelEvent& event) {}

[jam, 2011/08/15 19:54:54]

it looks like most of the functions in this class are pure virtual, so please do
the same here. we're trying to make most of the interfaces now not have default
empty implementations (i.e. tabcontentsdelegate/tabcontentsview etc).

[Nico, 2011/08/15 20:11:52]

What's the advantage of that? I then have to add empty implementations to the
win and linux ports and will break the builds of other teams who might have
subclassed this.

+
+  virtual void SetHasHorizontalScrollbar(bool has_horizontal_scrollbar) {}
+  virtual void SetScrollOffsetPinning(
+      bool is_pinned_to_left, bool is_pinned_to_right) {}
+
   void set_popup_type(WebKit::WebPopupType popup_type) {
     popup_type_ = popup_type;
   }
   WebKit::WebPopupType popup_type() const { return popup_type_; }
 
   // Subclasses should override this method to do what is appropriate to set
   // the custom background for their platform.
   virtual void SetBackground(const SkBitmap& background);
   const SkBitmap& background() const { return background_; }
 
@@ skipping 22 matching lines @@
 
   // The current reserved area in view coordinates where contents should not be
   // rendered to draw the resize corner, sidebar mini tabs etc.
   gfx::Rect reserved_rect_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostView);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_H_