Convert view manager to surfaces with uploading shim in client lib

mojo/services/public/interfaces/native_viewport/native_viewport.mojom

Index: mojo/services/public/interfaces/native_viewport/native_viewport.mojom
diff --git a/mojo/services/public/interfaces/native_viewport/native_viewport.mojom b/mojo/services/public/interfaces/native_viewport/native_viewport.mojom
index dd04f5cb17dcc927bbd3a4a06dcbc661e7963f4b..a182a1493c053d1bbd64403ba017297e653ee095 100644
--- a/mojo/services/public/interfaces/native_viewport/native_viewport.mojom
+++ b/mojo/services/public/interfaces/native_viewport/native_viewport.mojom
@@ -11,17 +11,17 @@ module mojo {
 
 [Client=NativeViewportClient]
 interface NativeViewport {
-  Create(Rect bounds);
+  Create(Size size);
   Show();
   Hide();
   Close();
-  SetBounds(Rect bounds);
+  SetBounds(Size size);
   SubmittedFrame(SurfaceId surface_id);
 };
 
 interface NativeViewportClient {
   OnCreated(uint64 native_viewport_id);
-  OnBoundsChanged(Rect bounds);
+  OnBoundsChanged(Size size);
   OnDestroyed();
   OnEvent(Event event) => ();
 };