aura: Remove CreateOffscreenContext from ui::ContextFactory.

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 53 matching lines @@
         'base/switches.cc',
         'base/switches.h',
         'base/tiling_data.cc',
         'base/tiling_data.h',
         'base/util.h',
         'debug/debug_colors.cc',
         'debug/debug_colors.h',
         'debug/debug_rect_history.cc',
         'debug/debug_rect_history.h',
         'debug/devtools_instrumentation.h',
+        'debug/fake_context_provider.cc',
+        'debug/fake_context_provider.h',
         'debug/fake_web_graphics_context_3d.cc',
         'debug/fake_web_graphics_context_3d.h',
         'debug/frame_rate_counter.cc',
         'debug/frame_rate_counter.h',
         'debug/layer_tree_debug_state.cc',
         'debug/layer_tree_debug_state.h',
         'debug/overdraw_metrics.cc',
         'debug/overdraw_metrics.h',
         'debug/paint_time_counter.cc',
         'debug/paint_time_counter.h',
@@ skipping 296 matching lines @@
         'trees/thread_proxy.cc',
         'trees/thread_proxy.h',
         'trees/tree_synchronizer.cc',
         'trees/tree_synchronizer.h',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }