Change ppapi C++ comment style into C.

ppapi/c/dev/pp_video_dev.h

Index: ppapi/c/dev/pp_video_dev.h
diff --git a/ppapi/c/dev/pp_video_dev.h b/ppapi/c/dev/pp_video_dev.h
index 6f67c1eb406414e5e53a85c825cfc41e466803a6..0699994c147ca391693d6c66aadf9477919afb90 100644
--- a/ppapi/c/dev/pp_video_dev.h
+++ b/ppapi/c/dev/pp_video_dev.h
@@ -1,7 +1,7 @@
-// Copyright (c) 2010 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) 2010 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 PPAPI_C_DEV_PP_VIDEO_DEV_H_
 #define PPAPI_C_DEV_PP_VIDEO_DEV_H_
 
@@ -333,4 +333,5 @@ struct PP_VideoDecoderConfig_Dev {
   PP_VideoDecodeEventHandler_Func_Dev event_handler;
 };
 
-#endif  // PPAPI_C_DEV_PP_VIDEO_DEV_H_
+#endif  /* PPAPI_C_DEV_PP_VIDEO_DEV_H_ */
+