Update PPAPI IDL generator to define versioned structs, and unversioned typedef.

ppapi/c/dev/ppb_directory_reader_dev.h

Index: ppapi/c/dev/ppb_directory_reader_dev.h
diff --git a/ppapi/c/dev/ppb_directory_reader_dev.h b/ppapi/c/dev/ppb_directory_reader_dev.h
index 2a49ee91f4b2377b4a1bdcb4b9cbaa5dcb39adc6..8c742afb81c83069b4d5a2e903714b4b3c8a3c74 100644
--- a/ppapi/c/dev/ppb_directory_reader_dev.h
+++ b/ppapi/c/dev/ppb_directory_reader_dev.h
@@ -22,7 +22,7 @@ PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_DirectoryEntry_Dev, 8);
 #define PPB_DIRECTORYREADER_DEV_INTERFACE_0_5 "PPB_DirectoryReader(Dev);0.5"
 #define PPB_DIRECTORYREADER_DEV_INTERFACE PPB_DIRECTORYREADER_DEV_INTERFACE_0_5
 
-struct PPB_DirectoryReader_Dev {
+struct PPB_DirectoryReader_Dev_0_5 {
   // Creates a DirectoryReader for the given directory.  Upon success, the
   // corresponding directory is classified as "in use" by the resulting
   // DirectoryReader object until such time as the DirectoryReader object is
@@ -55,4 +55,6 @@ struct PPB_DirectoryReader_Dev {
                           struct PP_CompletionCallback callback);
 };
 
+typedef struct PPB_DirectoryReader_Dev_0_5 PPB_DirectoryReader_Dev;
+
 #endif  /* PPAPI_C_DEV_PPB_DIRECTORY_READER_DEV_H_ */