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

content/browser/renderer_host/render_view_host.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 "content/browser/renderer_host/render_view_host.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 991 matching lines @@
 void RenderViewHost::OnMsgDidContentsPreferredSizeChange(
     const gfx::Size& new_size) {
   RenderViewHostDelegate::View* view = delegate_->GetViewDelegate();
   if (!view)
     return;
   view->UpdatePreferredSize(new_size);
 }
 
 void RenderViewHost::OnMsgDidChangeScrollbarsForMainFrame(
     bool has_horizontal_scrollbar, bool has_vertical_scrollbar) {
-  // TODO(thakis): Implement, http://crbug.com/90228
+  if (view())
+    view()->SetHasHorizontalScrollbar(has_horizontal_scrollbar);
 }
 
 void RenderViewHost::OnMsgDidChangeScrollOffsetPinningForMainFrame(
     bool is_pinned_to_left, bool is_pinned_to_right) {
-  // TODO(thakis): Implement, http://crbug.com/90228
+  if (view())
+    view()->SetScrollOffsetPinning(is_pinned_to_left, is_pinned_to_right);
 }
 
 void RenderViewHost::OnMsgDidChangeNumWheelEvents(int count) {

[Mark Mentovai, 2011/08/15 14:43:57]

Will we be using this at all?

[Nico, 2011/08/15 16:39:46]

Good question. WebKit2 piped it through along with the two other values, so
"maybe". I notice that they somehow manage to not wait for unhandled scrolls
from the renderer right after page load (you can swipe through many pages very
quickly in Safari, while we currently have to wait for every page to load enough
that the renderer can return a swipe event). So maybe I'll need it for that
soon. If it turns out I won't need it, I'll remove the plumbing for this again.

-  // TODO(thakis): Implement, http://crbug.com/90228
 }
 
 void RenderViewHost::OnMsgSelectionChanged(const std::string& text,
                                            const ui::Range& range,
                                            const gfx::Point& start,
                                            const gfx::Point& end) {
   if (view())
     view()->SelectionChanged(text, range, start, end);
 }
 
@@ skipping 322 matching lines @@
   if (view) {
     view->ShowPopupMenu(params.bounds,
                         params.item_height,
                         params.item_font_size,
                         params.selected_item,
                         params.popup_items,
                         params.right_aligned);
   }
 }
 #endif