Fix header guard in cc/surfaces/display

cc/surfaces/display.h

Index: cc/surfaces/display.h
diff --git a/cc/surfaces/display.h b/cc/surfaces/display.h
index ff2632b8cd716dac4f7e7e9e1d56d1bb3db3b6db..2856016c9d12967730d8e70d787834428c3fd9a5 100644
--- a/cc/surfaces/display.h
+++ b/cc/surfaces/display.h
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#ifndef CC_SURFACES_DISPLAY_H_
+#define CC_SURFACES_DISPLAY_H_
+
 #include "base/memory/scoped_ptr.h"
 
 #include "cc/layers/delegated_frame_resource_collection.h"
@@ -90,3 +93,5 @@ class CC_SURFACES_EXPORT Display
 };
 
 }  // namespace cc
+
+#endif  // CC_SURFACES_DISPLAY_H_