Change ppapi C++ comment style into C.

ppapi/c/dev/ppb_file_system_dev.h

Index: ppapi/c/dev/ppb_file_system_dev.h
diff --git a/ppapi/c/dev/ppb_file_system_dev.h b/ppapi/c/dev/ppb_file_system_dev.h
index 2a8dbf35245e9fa303116e1e7b55632d9b94a758..69b18bda8e189f3f3aafa1a1f19a81f3542dfdf8 100644
--- a/ppapi/c/dev/ppb_file_system_dev.h
+++ b/ppapi/c/dev/ppb_file_system_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_FILE_SYSTEM_DEV_H_
 #define PPAPI_C_DEV_PPB_FILE_SYSTEM_DEV_H_
 
@@ -26,4 +26,5 @@ struct PPB_FileSystem_Dev {
                   struct PP_CompletionCallback callback);
 };
 
-#endif  // PPAPI_C_DEV_PPB_FILE_SYSTEM_DEV_H_
+#endif  /* PPAPI_C_DEV_PPB_FILE_SYSTEM_DEV_H_ */
+