Change ppapi C++ comment style into C.

ppapi/c/pp_stdint.h

-// 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_STDINT_H_
 #define PPAPI_C_PP_STDINT_H_
 
 /**
  * @file
  * Provides a definition of C99 sized types
  * across different compilers.
  *
  * @addtogroup PP
  * @{
  */
 #if defined(_MSC_VER)
 
 typedef unsigned char uint8_t;
 typedef signed char int8_t;
 typedef unsigned short uint16_t;
 typedef short int16_t;
 typedef unsigned int uint32_t;
 typedef int int32_t;
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
 
 #else
 #include <stdint.h>
 #endif
 
-#include <stddef.h>  // Needed for size_t.
+#include <stddef.h>  /* Needed for size_t. */
 
 /**
  * @}
  * End addtogroup PP
  */
-#endif  // PPAPI_C_PP_STDINT_H_
+#endif  /* PPAPI_C_PP_STDINT_H_ */
+