Getting rid of SurfaceIdHandler as it is no longer needed.

ui/aura/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")
 import("//testing/test.gni")
 
 component("aura") {
   sources = [
     "../wm/public/activation_change_observer.cc",
@@ skipping 76 matching lines @@
     "mus/mus_context_factory.h",
     "mus/mus_types.h",
     "mus/mus_util.cc",
     "mus/mus_util.h",
     "mus/os_exchange_data_provider_mus.cc",
     "mus/os_exchange_data_provider_mus.h",
     "mus/property_converter.cc",
     "mus/property_converter.h",
     "mus/property_utils.cc",
     "mus/property_utils.h",
-    "mus/surface_id_handler.h",
     "mus/text_input_client_impl.cc",
     "mus/text_input_client_impl.h",
     "mus/window_compositor_frame_sink.cc",
     "mus/window_compositor_frame_sink.h",
     "mus/window_manager_delegate.cc",
     "mus/window_manager_delegate.h",
     "mus/window_mus.h",
     "mus/window_port_mus.cc",
     "mus/window_port_mus.h",
     "mus/window_tree_client.cc",
@@ skipping 257 matching lines @@
   ]
 
   if (is_linux) {
     deps += [ "//third_party/mesa" ]
   }
 
   data_deps = [
     "//third_party/mesa:osmesa",
   ]
 }