Change ppapi C++ comment style into C.

ppapi/c/dev/ppb_video_decoder_dev.h

Index: ppapi/c/dev/ppb_video_decoder_dev.h
diff --git a/ppapi/c/dev/ppb_video_decoder_dev.h b/ppapi/c/dev/ppb_video_decoder_dev.h
index 1e93780e0a739e7463c1805877900aa39b46d5ef..ceb4c800a52ee8f8326a1d1bdf0a7a3f81e8aa96 100644
--- a/ppapi/c/dev/ppb_video_decoder_dev.h
+++ b/ppapi/c/dev/ppb_video_decoder_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_PPB_VIDEO_DECODER_DEV_H_
 #define PPAPI_C_DEV_PPB_VIDEO_DECODER_DEV_H_
 
@@ -84,4 +84,5 @@ struct PPB_VideoDecoder_Dev {
       struct PP_VideoUncompressedDataBuffer_Dev* buffer);
 };
 
-#endif  // PPAPI_C_DEV_PPB_VIDEO_DECODER_DEV_H_
+#endif  /* PPAPI_C_DEV_PPB_VIDEO_DECODER_DEV_H_ */
+