Add wallpaper experimental api framework and add a simple category list.

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
@@ skipping 4063 matching lines @@
           'sources': [
             # Only extension API implementations should go here.
             'browser/accessibility/accessibility_extension_api.cc',
             'browser/accessibility/accessibility_extension_api.h',
             'browser/bookmarks/bookmark_extension_api.cc',
             'browser/bookmarks/bookmark_extension_api.h',
             'browser/chromeos/extensions/echo_private_api.cc',
             'browser/chromeos/extensions/echo_private_api.h',
             'browser/chromeos/extensions/file_browser_private_api.cc',
             'browser/chromeos/extensions/file_browser_private_api.h',
+            'browser/chromeos/extensions/wallpaper_manager_api.cc',
+            'browser/chromeos/extensions/wallpaper_manager_api.h',
             'browser/chromeos/media/media_player_extension_api.cc',
             'browser/chromeos/media/media_player_extension_api.h',
             'browser/download/download_extension_api.cc',
             'browser/download/download_extension_api.h',
             'browser/history/history_extension_api.cc',
             'browser/history/history_extension_api.h',
             'browser/history/top_sites_extension_api.cc',
             'browser/history/top_sites_extension_api.h',
             'browser/infobars/infobar_extension_api.cc',
             'browser/infobars/infobar_extension_api.h',
@@ skipping 1021 matching lines @@
         'browser/metrics/proto/study.proto',
       ],
       'variables': {
         'proto_in_dir': 'browser/metrics/proto',
         'proto_out_dir': 'chrome/browser/metrics/proto',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }