Add a Display and ContextProvider concept to mojom, use to recreate

services/native_viewport/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("//mojo/public/mojo_application.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
   import("//build/config/android/rules.gni")
@@ skipping 39 matching lines @@
       "//services/gles2",
       "//ui/gl",
     ]
   }
 }
 
 source_set("lib") {
   sources = [
     "native_viewport_impl.cc",
     "native_viewport_impl.h",
+    "onscreen_context_provider.cc",
+    "onscreen_context_provider.h",
     "platform_viewport.h",
     "platform_viewport_android.cc",
     "platform_viewport_android.h",
     "platform_viewport_headless.cc",
     "platform_viewport_headless.h",
     "platform_viewport_stub.cc",
     "platform_viewport_win.cc",
     "platform_viewport_x11.cc",
     "viewport_surface.cc",
     "viewport_surface.h",
@@ skipping 35 matching lines @@
   if (use_x11) {
     deps += [ "//ui/platform_window/x11" ]
   } else {
     sources -= [ "platform_viewport_x11.cc" ]
   }
 
   if (is_win) {
     deps += [ "//ui/platform_window/win" ]
   }
 }