Mac[Views]: Make native menus more responsive by pumping private runloop modes.

ui/views/controls/menu/menu_runner_impl_cocoa.mm

 // Copyright 2014 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 "ui/views/controls/menu/menu_runner_impl_cocoa.h"
 
 #include "base/mac/sdk_forward_declarations.h"
 #import "ui/base/cocoa/menu_controller.h"
 #include "ui/base/models/menu_model.h"
 #include "ui/events/base_event_utils.h"
@@ skipping 85 matching lines @@
 
 MenuRunnerImplCocoa::MenuRunnerImplCocoa(
     ui::MenuModel* menu,
     const base::Closure& on_menu_closed_callback)
     : running_(false),
       delete_after_run_(false),
       closing_event_time_(base::TimeTicks()),
       on_menu_closed_callback_(on_menu_closed_callback) {
   menu_controller_.reset(
       [[MenuController alloc] initWithModel:menu useWithPopUpButtonCell:NO]);
+  [menu_controller_ setPostItemSelectedAsTask:YES];
 }
 
 bool MenuRunnerImplCocoa::IsRunning() const {
   return running_;
 }
 
 void MenuRunnerImplCocoa::Release() {
   if (IsRunning()) {
     if (delete_after_run_)
       return;  // We already canceled.
@@ skipping 54 matching lines @@
 
 base::TimeTicks MenuRunnerImplCocoa::GetClosingEventTime() const {
   return closing_event_time_;
 }
 
 MenuRunnerImplCocoa::~MenuRunnerImplCocoa() {
 }
 
 }  // namespace internal
 }  // namespace views