Remove extraneous namespaces

mojo/examples/surfaces_app/child.mojom

 // 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 "mojo/services/public/interfaces/geometry/geometry.mojom"
 import "mojo/services/public/interfaces/surfaces/quads.mojom"
 import "mojo/services/public/interfaces/surfaces/surface_id.mojom"
 
 interface Child {
-  ProduceFrame(mojo.surfaces.Color color, mojo.Size size) =>
-      (mojo.surfaces.SurfaceId id);
+  ProduceFrame(mojo.Color color, mojo.Size size) =>
+      (mojo.SurfaceId id);
 };