Move InterfaceProvider into the shell::mojom namespace like the rest of the shell interfaces.

mojo/shell/public/interfaces/shell.mojom

Index: mojo/shell/public/interfaces/shell.mojom
diff --git a/mojo/shell/public/interfaces/shell.mojom b/mojo/shell/public/interfaces/shell.mojom
index 2101500608fe03296aa1755f01e8249075306bce..c3f15be8e6ba76e9859dfa4d5efc03c8742847ea 100644
--- a/mojo/shell/public/interfaces/shell.mojom
+++ b/mojo/shell/public/interfaces/shell.mojom
@@ -62,8 +62,8 @@ interface Shell {
   // establish the connection to |application_url|. If no content handler is
   // used |content_handler_id| is kInvalidApplicationID.
   ConnectToApplication(mojo.URLRequest application_url,
-                       mojo.InterfaceProvider&? remote_interfaces,
-                       mojo.InterfaceProvider? local_interfaces,
+                       InterfaceProvider&? remote_interfaces,
+                       InterfaceProvider? local_interfaces,
                        CapabilityFilter filter) =>
       (uint32 application_id, uint32 content_handler_id);