Change ppapi C++ comment style into C.

ppapi/c/dev/ppb_audio_dev.h

Index: ppapi/c/dev/ppb_audio_dev.h
diff --git a/ppapi/c/dev/ppb_audio_dev.h b/ppapi/c/dev/ppb_audio_dev.h
index f29830294006658755a0a561dd83c8362ceafd65..8d4e4c5ef2598417223d099a5b382dd4f18005a9 100644
--- a/ppapi/c/dev/ppb_audio_dev.h
+++ b/ppapi/c/dev/ppb_audio_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_AUDIO_DEV_H_
 #define PPAPI_C_DEV_PPB_AUDIO_DEV_H_
 
@@ -69,4 +69,5 @@ struct PPB_Audio_Dev {
   PP_Bool (*StopPlayback)(PP_Resource audio);
 };
 
-#endif  // PPAPI_C_DEV_PPB_DEVICE_CONTEXT_AUDIO_DEV_H_
+#endif  /* PPAPI_C_DEV_PPB_DEVICE_CONTEXT_AUDIO_DEV_H_ */
+