services/ui: Create a proper component for the client-lib.

services/ui/public/cpp/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.
 
-source_set("cpp") {
+component("cpp") {
   sources = [
     "bitmap_uploader.h",
     "context_provider.h",
     "gles2_context.h",
     "input_event_handler.h",
     "lib/bitmap_uploader.cc",
     "lib/command_buffer_client_impl.cc",
     "lib/command_buffer_client_impl.h",
     "lib/context_provider.cc",
     "lib/gles2_context.cc",
     "lib/in_flight_change.cc",
     "lib/in_flight_change.h",
     "lib/output_surface.cc",
     "lib/property_type_converters.cc",
     "lib/raster_thread_helper.cc",
     "lib/scoped_window_ptr.cc",
     "lib/window.cc",
     "lib/window_observer.cc",
     "lib/window_private.cc",
     "lib/window_private.h",
     "lib/window_surface.cc",
     "lib/window_tree_client.cc",
     "lib/window_tree_client_delegate.cc",
     "lib/window_tree_host_factory.cc",
     "output_surface.h",
     "property_type_converters.h",
     "raster_thread_helper.h",
     "scoped_window_ptr.h",
+    "ui_export.h",
     "window.h",
     "window_manager_delegate.cc",
     "window_manager_delegate.h",
     "window_observer.h",
     "window_property.h",
     "window_surface.h",
     "window_surface_client.h",
     "window_tracker.h",
     "window_tree_client.h",
     "window_tree_client_delegate.h",
@@ skipping 24 matching lines @@
     "//services/ui/public/interfaces",
     "//ui/display",
     "//ui/events",
     "//ui/gfx/geometry",
   ]
 
   data_deps = [
     "//services/ui",
   ]
 
-  defines = [ "GL_GLEXT_PROTOTYPES" ]
+  defines = [
+    "GL_GLEXT_PROTOTYPES",
+    "UI_IMPLEMENTATION",
+  ]
 }