Change ppapi C++ comment style into C.

ppapi/c/dev/ppb_zoom_dev.h

Index: ppapi/c/dev/ppb_zoom_dev.h
diff --git a/ppapi/c/dev/ppb_zoom_dev.h b/ppapi/c/dev/ppb_zoom_dev.h
index c44e8c5fd5575714dfa20f99adc472c26111aaee..b450d3288f54901df064033c09003d1c97a164ba 100644
--- a/ppapi/c/dev/ppb_zoom_dev.h
+++ b/ppapi/c/dev/ppb_zoom_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_ZOOM_DEV_H_
 #define PPAPI_C_DEV_PPB_ZOOM_DEV_H_
 
@@ -25,4 +25,5 @@ struct PPB_Zoom_Dev {
                             double maximium_factor);
 };
 
-#endif  // PPAPI_C_DEV_PPB_ZOOM_DEV_H_
+#endif  /* PPAPI_C_DEV_PPB_ZOOM_DEV_H_ */
+