[Mac] Add cocoa implementation for sidebar extension action support

chrome/chrome_browser_ui.gypi

 # Copyright 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.
 
 {
   'variables': {
     # There are two sections of sources:
     # * "Platform"-based sources (OS, toolkit, etc.)
     # * Feature/directory-based sources (e.g., history, printing)
 
@@ skipping 1177 matching lines @@
       'browser/ui/cocoa/profiles/profile_signin_confirmation_view_controller.h',
       'browser/ui/cocoa/profiles/profile_signin_confirmation_view_controller.mm',
       'browser/ui/cocoa/profiles/user_manager_mac.h',
       'browser/ui/cocoa/profiles/user_manager_mac.mm',
       'browser/ui/cocoa/rect_path_utils.h',
       'browser/ui/cocoa/rect_path_utils.mm',
       'browser/ui/cocoa/restart_browser.h',
       'browser/ui/cocoa/restart_browser.mm',
       'browser/ui/cocoa/screen_capture_notification_ui_cocoa.h',
       'browser/ui/cocoa/screen_capture_notification_ui_cocoa.mm',
+      'browser/ui/cocoa/sidebar_controller.h',
+      'browser/ui/cocoa/sidebar_controller.mm',
       'browser/ui/cocoa/simple_message_box_mac.mm',
       'browser/ui/cocoa/spinner_view.h',
       'browser/ui/cocoa/spinner_view.mm',
       'browser/ui/cocoa/sprite_view.h',
       'browser/ui/cocoa/sprite_view.mm',
       'browser/ui/cocoa/ssl_client_certificate_selector_cocoa.h',
       'browser/ui/cocoa/ssl_client_certificate_selector_cocoa.mm',
       'browser/ui/cocoa/status_bubble_mac.h',
       'browser/ui/cocoa/status_bubble_mac.mm',
       'browser/ui/cocoa/styled_text_field.h',
@@ skipping 1994 matching lines @@
           ],
           'sources': [
             '<@(chrome_browser_ui_non_mobile_sources)',
             '<@(chrome_browser_ui_omnibox_non_mobile_sources)',
           ],
         }],
       ],
     },
   ],
 }