[NaCl SDK] Consistent use of copyright header.

native_client_sdk/src/examples/api/graphics_3d/graphics_3d.cc

-/* Copyright (c) 2012 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.
- */
+// Copyright (c) 2012 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.
 
 //-----------------------------------------------------------------------------
 // The spinning Cube
 //-----------------------------------------------------------------------------
 
 #define _USE_MATH_DEFINES 1
 #include <limits.h>
 #include <math.h>
 #include <stdarg.h>
 #include <stddef.h>
@@ skipping 593 matching lines @@
     };
     return &instance_interface;
   }
   return NULL;
 }
 
 /**
  * Called before the plugin module is unloaded.
  */
 PP_EXPORT void PPP_ShutdownModule() {}