Re-land alexbost's experimental offscreenTabs API.

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',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 941 matching lines @@
         'browser/download/save_package_file_picker.cc',
         'browser/download/save_package_file_picker.h',
         'browser/enumerate_modules_model_win.cc',
         'browser/enumerate_modules_model_win.h',
         'browser/event_disposition.cc',
         'browser/event_disposition.h',
         'browser/extensions/api/app/app_api.cc',
         'browser/extensions/api/app/app_api.h',
         'browser/extensions/api/dns/dns_api.cc',
         'browser/extensions/api/dns/dns_api.h',
+        'browser/extensions/api/offscreen_tabs/offscreen_tabs_api.cc',
+        'browser/extensions/api/offscreen_tabs/offscreen_tabs_api.h',
+        'browser/extensions/api/offscreen_tabs/offscreen_tabs_constants.cc',
+        'browser/extensions/api/offscreen_tabs/offscreen_tabs_constants.h',
         'browser/extensions/api/permissions/permissions_api.cc',
         'browser/extensions/api/permissions/permissions_api.h',
         'browser/extensions/api/permissions/permissions_api_helpers.cc',
         'browser/extensions/api/permissions/permissions_api_helpers.h',
         'browser/extensions/api/serial/serial_api.cc',
         'browser/extensions/api/serial/serial_api.h',
         'browser/extensions/api/socket/socket.cc',
         'browser/extensions/api/socket/socket.h',
         'browser/extensions/api/socket/socket_api.cc',
         'browser/extensions/api/socket/socket_api.h',
@@ skipping 4513 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/history/in_memory_url_index_cache.proto' ],
       'variables': {
         'proto_in_dir': 'browser/history',
         'proto_out_dir': 'chrome/browser/history',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }