Make it possible to change the viewport size

mojo/services/public/interfaces/window_manager/window_manager_internal.mojom

Index: mojo/services/public/interfaces/window_manager/window_manager_internal.mojom
diff --git a/mojo/services/public/interfaces/window_manager/window_manager_internal.mojom b/mojo/services/public/interfaces/window_manager/window_manager_internal.mojom
index 0ad089bbbf60bbd708971f7fbff7d4a262868415..c76bc729e6ef1c8717cb10955b6fe7dec302baea 100644
--- a/mojo/services/public/interfaces/window_manager/window_manager_internal.mojom
+++ b/mojo/services/public/interfaces/window_manager/window_manager_internal.mojom
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import "mojo/services/public/interfaces/geometry/geometry.mojom";
 import "mojo/services/public/interfaces/input_events/input_events.mojom";
 
 module mojo {
@@ -11,6 +12,9 @@ module mojo {
 interface WindowManagerInternalClient {
   // Dispatches the specified input event to the specified view.
   DispatchInputEventToView(uint32 view_id, mojo.Event event);
+
+  // Sets the native viewport size.
+  SetViewportSize(mojo.Size size);
 };
 
 }