Move DisplayCompositor code to new component.

services/ui/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 = [
-    "display_compositor.cc",
-    "display_compositor.h",
     "display_output_surface.cc",
     "display_output_surface.h",
   ]
 
   deps = [
     "//base",
     "//cc",
     "//cc/ipc:interfaces",
     "//cc/surfaces",
     "//components/display_compositor",
     "//gpu/command_buffer/client",
     "//gpu/command_buffer/client:gles2_interface",
     "//gpu/ipc:command_buffer",
     "//ui/display/types",
     "//ui/gfx",
     "//ui/gfx/geometry/mojo",
   ]
 
   if (use_ozone) {
     sources += [
       "display_output_surface_ozone.cc",
       "display_output_surface_ozone.h",
     ]
     deps += [
       "//gpu/command_buffer/common",
       "//ui/gl",
     ]
   }
 }