Rewire Android WebView's compositor changed signal.

android_webview/android_webview.gyp

 # Copyright 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,
     'system_webview_package_name%': 'com.android.webview',
   },
   'targets': [
     {
@@ skipping 316 matching lines @@
         'browser/aw_result_codes.h',
         'browser/aw_ssl_host_state_delegate.cc',
         'browser/aw_ssl_host_state_delegate.h',
         'browser/aw_web_preferences_populater.cc',
         'browser/aw_web_preferences_populater.h',
         'browser/browser_view_renderer.cc',
         'browser/browser_view_renderer.h',
         'browser/browser_view_renderer_client.h',
         'browser/child_frame.cc',
         'browser/child_frame.h',
+        'browser/compositor_id.cc',
+        'browser/compositor_id.h',
         'browser/deferred_gpu_command_service.cc',
         'browser/deferred_gpu_command_service.h',
         'browser/find_helper.cc',
         'browser/find_helper.h',
         'browser/gl_view_renderer_manager.cc',
         'browser/gl_view_renderer_manager.h',
         'browser/hardware_renderer.cc',
         'browser/hardware_renderer.h',
         'browser/icon_helper.cc',
         'browser/icon_helper.h',
@@ skipping 162 matching lines @@
           'includes': [ 'apk/system_webview_apk_common.gypi' ],
         },
       ],
     }]
   ],
   'includes': [
     'android_webview_tests.gypi',
     'apk/system_webview_paks.gypi',
   ],
 }