Move nsimage_cache into base so that it can be accessed from outside of chrome

chrome/chrome.gyp

 # Copyright (c) 2009 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': {
     'chromium_code': 1,
 
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
@@ skipping 1056 matching lines @@
         'browser/cocoa/infobar_gradient_view.mm',
         'browser/cocoa/infobar_test_helper.h',
         'browser/cocoa/infobar_text_field.h',
         'browser/cocoa/infobar_text_field.mm',
         'browser/cocoa/keyword_editor_cocoa_controller.h',
         'browser/cocoa/keyword_editor_cocoa_controller.mm',
         'browser/cocoa/location_bar_view_mac.h',
         'browser/cocoa/location_bar_view_mac.mm',
         'browser/cocoa/menu_button.h',
         'browser/cocoa/menu_button.mm',
-        'browser/cocoa/nsimage_cache.h',
-        'browser/cocoa/nsimage_cache.mm',
         'browser/cocoa/nswindow_local_state.h',
         'browser/cocoa/nswindow_local_state.mm',
         'browser/cocoa/page_info_window_controller.h',
         'browser/cocoa/page_info_window_controller.mm',
         'browser/cocoa/page_info_window_mac.h',
         'browser/cocoa/page_info_window_mac.mm',
         'browser/cocoa/preferences_localizer.h',
         'browser/cocoa/preferences_localizer.mm',
         'browser/cocoa/preferences_window_controller.h',
         'browser/cocoa/preferences_window_controller.mm',
@@ skipping 5718 matching lines @@
               'defines': [
                 'POSIX',
               ],
             }],
           ],
         },
       ],  # targets when chrome_personalization==1
     }],
   ],  # 'conditions'
 }