Revert of Mandoline: Remove native_viewport.mojom

components/view_manager/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("//third_party/mojo/src/mojo/public/mojo_application.gni")
 
 source_set("native_viewport") {
   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",
@@ skipping 28 matching lines @@
   if (use_x11) {
     deps += [ "//ui/platform_window/x11" ]
   } else {
     sources -= [ "platform_viewport_x11.cc" ]
   }
 
   if (is_win) {
     deps += [ "//ui/platform_window/win" ]
   }
 }