Remove all traces of compositing reasons from cc

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 111 matching lines @@
         'debug/unittest_only_benchmark.h',
         'debug/unittest_only_benchmark_impl.cc',
         'debug/unittest_only_benchmark_impl.h',
         'input/input_handler.h',
         'input/page_scale_animation.cc',
         'input/page_scale_animation.h',
         'input/top_controls_manager.cc',
         'input/top_controls_manager.h',
         'input/top_controls_manager_client.h',
         'layers/append_quads_data.h',
-        'layers/compositing_reasons.h',
         'layers/content_layer.cc',
         'layers/content_layer.h',
         'layers/content_layer_client.h',
         'layers/contents_scaling_layer.cc',
         'layers/contents_scaling_layer.h',
         'layers/delegated_frame_provider.cc',
         'layers/delegated_frame_provider.h',
         'layers/delegated_frame_resource_collection.cc',
         'layers/delegated_frame_resource_collection.h',
         'layers/delegated_renderer_layer.cc',
@@ 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, ],
     },
   ],
 }