mac: History swiping doesn't work right with iframes.

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm

 // Copyright (c) 2012 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.
 
 #import "chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.h"
 
 #include <cmath>
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 88 matching lines @@
   view_id_util::UnsetID(view);
 }
 
 // Handle an event. All incoming key and mouse events flow through this
 // delegate method if implemented. Return YES if the event is fully handled, or
 // NO if normal processing should take place.
 - (BOOL)handleEvent:(NSEvent*)event {
   return [historySwiper_ handleEvent:event];
 }
 
-// Notification that a wheel event was unhandled.
-- (void)gotUnhandledWheelEvent {
-  [historySwiper_ gotUnhandledWheelEvent];
-}
-
-// Notification of scroll offset pinning.
-- (void)scrollOffsetPinnedToLeft:(BOOL)left toRight:(BOOL)right {
-  [historySwiper_ scrollOffsetPinnedToLeft:left toRight:right];
-}
-
-// Notification of whether the view has a horizontal scrollbar.
-- (void)setHasHorizontalScrollbar:(BOOL)has_horizontal_scrollbar {
-  [historySwiper_ setHasHorizontalScrollbar:has_horizontal_scrollbar];
+- (void)gotWheelEventConsumed:(BOOL)consumed {
+  [historySwiper_ gotWheelEventConsumed:consumed];
 }
 
 // NSWindow events.
 
 - (void)beginGestureWithEvent:(NSEvent*)event {
   [historySwiper_ beginGestureWithEvent:event];
 }
 
 - (void)endGestureWithEvent:(NSEvent*)event {
   [historySwiper_ endGestureWithEvent:event];
@@ skipping 132 matching lines @@
 }
 
 - (void)spellCheckEnabled:(BOOL)enabled checked:(BOOL)checked {
   spellcheckEnabled_ = enabled;
   spellcheckChecked_ = checked;
 }
 
 // END Spellchecking methods
 
 @end