Add very simple cc::Display implementation for surfaces.

cc/surfaces/display_client.h

Index: cc/surfaces/display_client.h
diff --git a/cc/surfaces/display_client.h b/cc/surfaces/display_client.h
new file mode 100644
index 0000000000000000000000000000000000000000..e5f0b31a10c7e02f3ea24190418d4d22e971bc8f
--- /dev/null
+++ b/cc/surfaces/display_client.h
@@ -0,0 +1,23 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CC_SURFACES_DISPLAY_CLIENT_H_
+#define CC_SURFACES_DISPLAY_CLIENT_H_
+
+#include "base/memory/scoped_ptr.h"
+
+namespace cc {
+
+class OutputSurface;
+
+class DisplayClient {
+ public:
+  virtual scoped_ptr<OutputSurface> CreateOutputSurface() = 0;
+
+ protected:
+  virtual ~DisplayClient() {}
+};
+}
+
+#endif  // CC_SURFACES_DISPLAY_CLIENT_H_