Allow drag-and-drop of zipped extensions on chrome://extensions

chrome/chrome_browser_extensions.gypi

 # Copyright (c) 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': {
     'chrome_browser_extensions_chromeos_sources': [
       'browser/extensions/api/diagnostics/diagnostics_api.cc',
       'browser/extensions/api/diagnostics/diagnostics_api.h',
       'browser/extensions/api/diagnostics/diagnostics_api_chromeos.cc',
@@ skipping 887 matching lines @@
       'browser/extensions/webstore_installer.h',
       'browser/extensions/webstore_standalone_installer.cc',
       'browser/extensions/webstore_standalone_installer.h',
       'browser/extensions/webstore_startup_installer.cc',
       'browser/extensions/webstore_startup_installer.h',
       'browser/extensions/window_controller.cc',
       'browser/extensions/window_controller.h',
       'browser/extensions/window_controller_list.cc',
       'browser/extensions/window_controller_list.h',
       'browser/extensions/window_controller_list_observer.h',
+      'browser/extensions/zipfile_installer.cc',
+      'browser/extensions/zipfile_installer.h',
     ],
     'chrome_browser_extensions_app_list_sources': [
       'browser/apps/drive/drive_app_converter.cc',
       'browser/apps/drive/drive_app_converter.h',
       'browser/apps/drive/drive_app_mapping.cc',
       'browser/apps/drive/drive_app_mapping.h',
       'browser/apps/drive/drive_app_provider.cc',
       'browser/apps/drive/drive_app_provider.h',
       'browser/apps/drive/drive_service_bridge.cc',
       'browser/apps/drive/drive_service_bridge.h',
@@ skipping 278 matching lines @@
         }],
         ['enable_app_list==1', {
           'sources': [
             '<@(chrome_browser_extensions_app_list_sources)',
           ],
         }]
       ],
     },
   ],
 }