Add version-specific defines for each C interface.

ppapi/c/dev/ppb_file_io_trusted_dev.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.
  */
 #ifndef PPAPI_C_DEV_PPB_FILE_IO_TRUSTED_DEV_H_
 #define PPAPI_C_DEV_PPB_FILE_IO_TRUSTED_DEV_H_
 
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
 
 struct PP_CompletionCallback;
 
-#define PPB_FILEIOTRUSTED_DEV_INTERFACE "PPB_FileIOTrusted(Dev);0.2"
+#define PPB_FILEIOTRUSTED_DEV_INTERFACE_0_2 "PPB_FileIOTrusted(Dev);0.2"
+#define PPB_FILEIOTRUSTED_DEV_INTERFACE PPB_FILEIOTRUSTED_DEV_INTERFACE_0_2
 
 // Available only to trusted implementations.
 struct PPB_FileIOTrusted_Dev {
   // Returns a file descriptor corresponding to the given FileIO object. On
   // Windows, returns a HANDLE; on all other platforms, returns a POSIX file
   // descriptor. The FileIO object must have been opened with a successful
   // call to FileIO::Open.  The file descriptor will be closed automatically
   // when the FileIO object is closed or destroyed.
   int32_t (*GetOSFileDescriptor)(PP_Resource file_io);
 
@@ skipping 14 matching lines @@
 
   // TODO(darin): Maybe unify the above into a single WillChangeFileSize
   // method?  The above methods have the advantage of mapping to PPB_FileIO
   // Write and SetLength calls.  WillChangeFileSize would require the caller to
   // compute the file size resulting from a Write call, which may be
   // undesirable.
 };
 
 #endif  /* PPAPI_C_DEV_PPB_FILE_IO_TRUSTED_DEV_H_ */