Allow to have a transparent UA dependent background.

cc/cc.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 578 matching lines @@
       'includes': [
         '../build/android/increase_size_for_speed.gypi',
       ],
       'conditions': [
         ['target_arch == "ia32" or target_arch == "x64"', {
           'sources': [
             'raster/texture_compressor_etc1_sse.cc',
             'raster/texture_compressor_etc1_sse.h',
           ],
         }],
+        # x11 build
+        ['use_x11==1', {
+          'dependencies': [
+            '../ui/gfx/x/gfx_x11.gyp:gfx_x11',
+          ],
+        }],
       ],
     },
     {
       # GN version: "//cc/proto"
       'target_name': 'cc_proto',
       'type': '<(component)',
       'sources': [
         'proto/begin_main_frame_and_commit_state.proto',
         'proto/commit_earlyout_reason.proto',
         'proto/compositor_message.proto',
@@ skipping 85 matching lines @@
         'surfaces/surface_resource_holder.cc',
         'surfaces/surface_resource_holder.h',
         'surfaces/surfaces_export.h',
       ],
       'includes': [
         '../build/android/increase_size_for_speed.gypi',
       ],
     },
   ],
 }