Quota: Factor out (Mock)QuotaManagerProxy into its own file for readability

webkit/storage_browser.gyp

 # Copyright 2013 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,
   },
   'targets': [
     {
@@ skipping 181 matching lines @@
         'browser/fileapi/transient_file_util.cc',
         'browser/fileapi/transient_file_util.h',
         'browser/fileapi/upload_file_system_file_element_reader.cc',
         'browser/fileapi/upload_file_system_file_element_reader.h',
         'browser/quota/quota_callbacks.h',
         'browser/quota/quota_client.h',
         'browser/quota/quota_database.cc',
         'browser/quota/quota_database.h',
         'browser/quota/quota_manager.cc',
         'browser/quota/quota_manager.h',
+        'browser/quota/quota_manager_proxy.cc',
+        'browser/quota/quota_manager_proxy.h',
         'browser/quota/quota_task.cc',
         'browser/quota/quota_task.h',
         'browser/quota/quota_temporary_storage_evictor.cc',
         'browser/quota/quota_temporary_storage_evictor.h',
         'browser/quota/special_storage_policy.cc',
         'browser/quota/special_storage_policy.h',
         'browser/quota/usage_tracker.cc',
         'browser/quota/usage_tracker.h',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
@@ skipping 20 matching lines @@
         'browser/fileapi/dump_file_system.cc',
       ],
       'dependencies': [
         '<(DEPTH)/base/base.gyp:base',
         '<(DEPTH)/webkit/storage_common.gyp:webkit_storage_common',
         'webkit_storage_browser',
       ],
     },
   ],
 }