Add version-specific defines for each C interface.

ppapi/c/ppb_image_data.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_PPB_IMAGE_DATA_H_
 #define PPAPI_C_PPB_IMAGE_DATA_H_
 
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
@@ skipping 54 matching lines @@
    * This value represents the row width in bytes. This may be different than
    * width * 4 since there may be padding at the end of the lines.
    */
   int32_t stride;
 };
 PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_ImageDataDesc, 16);
 /**
  * @}
  */
 
-#define PPB_IMAGEDATA_INTERFACE "PPB_ImageData;0.3"
+#define PPB_IMAGEDATA_INTERFACE_0_3 "PPB_ImageData;0.3"
+#define PPB_IMAGEDATA_INTERFACE PPB_IMAGEDATA_INTERFACE_0_3
 
 /**
  * @addtogroup Interfaces
  * @{
  */
 
 /**
  * The PPB_ImageData interface contains pointers to several functions for
  * determining the browser's treatment of image data.
  */
@@ skipping 82 matching lines @@
    *
    * @param[in] image_data A PP_Resource corresponding to image data.
    */
   void (*Unmap)(PP_Resource image_data);
 };
 /**
  * @}
  */
 
 #endif  /* PPAPI_C_PPB_IMAGE_DATA_H_ */