Change ppapi C++ comment style into C.

ppapi/c/pp_var.h

Index: ppapi/c/pp_var.h
diff --git a/ppapi/c/pp_var.h b/ppapi/c/pp_var.h
index 1695293ded81e93367f6fc1a5714b2304f27662f..9a429cbcfbf985a4d04eec70ce626f1955fcab85 100644
--- a/ppapi/c/pp_var.h
+++ b/ppapi/c/pp_var.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_PP_VAR_H_
 #define PPAPI_C_PP_VAR_H_
 
@@ -96,4 +96,5 @@ PP_INLINE struct PP_Var PP_MakeDouble(double value) {
  * @}
  * End addtogroup PP
  */
-#endif  // PPAPI_C_PP_VAR_H_
+#endif  /* PPAPI_C_PP_VAR_H_ */
+