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

chrome/browser/renderer_host/render_widget_host_view_views.cc

 // 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.
 
 #include "chrome/browser/renderer_host/render_widget_host_view_views.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 317 matching lines @@
   RenderWidgetHostView::SetBackground(background);
   if (host_)
     host_->Send(new ViewMsg_SetBackground(host_->routing_id(), background));
 }
 
 void RenderWidgetHostViewViews::SetVisuallyDeemphasized(
     const SkColor* color, bool animate) {
   // TODO(anicolao)
 }
 
+void RenderWidgetHostViewViews::UnhandledWheelEvent(
+    const WebKit::WebMouseWheelEvent& event) {
+}
+
+void RenderWidgetHostViewViews::SetHasHorizontalScrollbar(
+    bool has_horizontal_scrollbar) {
+}
+
+void RenderWidgetHostViewViews::SetScrollOffsetPinning(
+    bool is_pinned_to_left, bool is_pinned_to_right) {
+}
+
 void RenderWidgetHostViewViews::SelectRect(const gfx::Point& start,
                                            const gfx::Point& end) {
   if (host_)
     host_->Send(new ViewMsg_SelectRange(host_->routing_id(), start, end));
 }
 
 bool RenderWidgetHostViewViews::IsCommandIdChecked(int command_id) const {
   // TODO(varunjain): implement this and other menu delegate methods.
   NOTREACHED();
   return true;
@@ skipping 416 matching lines @@
 
 void RenderWidgetHostViewViews::FinishImeCompositionSession() {
   if (!has_composition_text_)
     return;
   if (host_)
     host_->ImeConfirmComposition();
   DCHECK(GetInputMethod());
   GetInputMethod()->CancelComposition(this);
   has_composition_text_ = false;
 }