Use local ids for Surfaces APIs that can only apply to local surfaces

mojo/services/surfaces/public/interfaces/surface_id.mojom

Index: mojo/services/surfaces/public/interfaces/surface_id.mojom
diff --git a/mojo/services/surfaces/public/interfaces/surface_id.mojom b/mojo/services/surfaces/public/interfaces/surface_id.mojom
index d68e2e7b69b65381e39e9c37398fb0cb69152da6..c02911a6c75566c950a9905deeea515d2281df3f 100644
--- a/mojo/services/surfaces/public/interfaces/surface_id.mojom
+++ b/mojo/services/surfaces/public/interfaces/surface_id.mojom
@@ -8,6 +8,12 @@ module mojo;
 // local part is allocated by the client using any scheme that avoids
 // duplicates. The namespace is allocated by the service and will be different
 // for each client (aka each connection to mojo.Surface).
+//
+// The special id_namespace value 0 is equivalent to the namespace of the
+// client. This can be used to created, destroy and submit frames to

[sky, 2015/01/13 18:14:27]

created->create

[jamesr, 2015/01/14 01:50:29]

Done.

+// surfaces before learning the namespace and to reference other surfaces
+// owned by the same client. The actual id namespace must be used to pass
+// surface ids to other clients for them to reference.
 struct SurfaceId {
   uint32 local;
   uint32 id_namespace;