Mojo: Implement support for |Foo&| mojom syntax

mojo/services/native_viewport/native_viewport.mojom

Index: mojo/services/native_viewport/native_viewport.mojom
diff --git a/mojo/services/native_viewport/native_viewport.mojom b/mojo/services/native_viewport/native_viewport.mojom
index 5535da1d1bedee31e8d96e22f7b3c1f9e9f9daba..42f1cbd138e427a96c32857bb622e0e51e1f128f 100644
--- a/mojo/services/native_viewport/native_viewport.mojom
+++ b/mojo/services/native_viewport/native_viewport.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 "../gles2/command_buffer.mojom"
 import "../public/interfaces/geometry/geometry.mojom"
 import "../public/interfaces/input_events/input_events.mojom"
 
@@ -14,7 +15,7 @@ interface NativeViewport {
   Hide();
   Close();
   SetBounds(Rect bounds);
-  CreateGLES2Context(handle<message_pipe> gles2_client);
+  CreateGLES2Context(CommandBuffer& gles2_client);
 };
 
 interface NativeViewportClient {