Pull parts of TopLevelDisplayClient into DisplayCompositor

components/mus/surfaces/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("//build/config/ui.gni")
 
 source_set("surfaces") {
   sources = [
     "direct_output_surface.cc",
     "direct_output_surface.h",
+    "display_compositor.cc",
+    "display_compositor.h",
     "surfaces_context_provider.cc",
     "surfaces_context_provider.h",
     "surfaces_context_provider_delegate.h",
     "surfaces_state.cc",
     "surfaces_state.h",
     "top_level_display_client.cc",
     "top_level_display_client.h",
   ]
 
   deps = [
@@ skipping 20 matching lines @@
   if (use_ozone) {
     sources += [
       "direct_output_surface_ozone.cc",
       "direct_output_surface_ozone.h",
       "ozone_gpu_memory_buffer_manager.cc",
       "ozone_gpu_memory_buffer_manager.h",
     ]
     deps += [ "//gpu/command_buffer/common" ]
   }
 }