Add a user id parameter to connections

mojo/shell/public/cpp/connection.h

Index: mojo/shell/public/cpp/connection.h
diff --git a/mojo/shell/public/cpp/connection.h b/mojo/shell/public/cpp/connection.h
index e05243fcb1a3a1b64dd21fe9a1f65796c3ec622b..39327a679621f9f733438a8a79432da199a83036 100644
--- a/mojo/shell/public/cpp/connection.h
+++ b/mojo/shell/public/cpp/connection.h
@@ -82,6 +82,9 @@ class Connection {
   // Returns the URL identifying the remote application on this connection.
   virtual const std::string& GetRemoteApplicationURL() = 0;
 
+  // Returns the User ID for the remote application.
+  virtual uint32_t GetRemoteUserID() const = 0;
+
   // Register a handler to receive an error notification on the pipe to the
   // remote application's InterfaceProvider.
   virtual void SetRemoteInterfaceProviderConnectionErrorHandler(