Allow ui::Compositor to disable commits during tab-switch

cc/BUILD.gn

 # Copyright 2014 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.
 
 import("//testing/test.gni")
 
 component("cc") {
   sources = [
     "animation/animation.cc",
     "animation/animation.h",
@@ skipping 495 matching lines @@
     "trees/draw_property_utils.h",
     "trees/layer_sorter.cc",
     "trees/layer_sorter.h",
     "trees/layer_tree_host.cc",
     "trees/layer_tree_host.h",
     "trees/layer_tree_host_client.h",
     "trees/layer_tree_host_common.cc",
     "trees/layer_tree_host_common.h",
     "trees/layer_tree_host_impl.cc",
     "trees/layer_tree_host_impl.h",
+    "trees/layer_tree_host_single_thread_client.h",
     "trees/layer_tree_impl.cc",
     "trees/layer_tree_impl.h",
     "trees/layer_tree_settings.cc",
     "trees/layer_tree_settings.h",
     "trees/occlusion.cc",
     "trees/occlusion.h",
     "trees/occlusion_tracker.cc",
     "trees/occlusion_tracker.h",
     "trees/property_tree.cc",
     "trees/property_tree.h",
@@ skipping 395 matching lines @@
     "//testing/gmock",
     "//testing/gtest",
     "//testing/perf",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 }
 # When adding support for isolates, please have a look at run-time dependencies
 # in the cc_unittests_run target in cc_tests.gyp.