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];
 }
 
 // NSWindow events.
 
 - (void)beginGestureWithEvent:(NSEvent*)event {
   [historySwiper_ beginGestureWithEvent:event];
 }
 
 - (void)endGestureWithEvent:(NSEvent*)event {
   [historySwiper_ endGestureWithEvent:event];
@@ skipping 68 matching lines @@
           spellcheckChecked_ ? NSOnState : NSOffState;
       [(id)item setState:checkedState];
     }
     *valid = spellcheckEnabled_;
     return YES;
   }
 
   return NO;
 }
 
+- (void)rendererHandledWheelEvent:(const blink::WebMouseWheelEvent&)event
+                         consumed:(BOOL)consumed {
+  [historySwiper_ rendererHandledWheelEvent:event consumed:consumed];
+}
+
 // Spellchecking methods
 // The next five methods are implemented here since this class is the first
 // responder for anything in the browser.
 
 // This message is sent whenever the user specifies that a word should be
 // changed from the spellChecker.
 - (void)changeSpelling:(id)sender {
   // Grab the currently selected word from the spell panel, as this is the word
   // that we want to replace the selected word in the text with.
   NSString* newWord = [[sender selectedCell] stringValue];
@@ skipping 44 matching lines @@
 }
 
 - (void)spellCheckEnabled:(BOOL)enabled checked:(BOOL)checked {
   spellcheckEnabled_ = enabled;
   spellcheckChecked_ = checked;
 }
 
 // END Spellchecking methods
 
 @end