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

ppapi/thunk/ppb_image_data_thunk.cc

Index: ppapi/thunk/ppb_image_data_thunk.cc
diff --git a/ppapi/thunk/ppb_image_data_thunk.cc b/ppapi/thunk/ppb_image_data_thunk.cc
index 00d9184565047211ceee98addecdd3228b5d527c..a7c4fc22042376302c62afa1a902787310fbe749 100644
--- a/ppapi/thunk/ppb_image_data_thunk.cc
+++ b/ppapi/thunk/ppb_image_data_thunk.cc
@@ -76,7 +76,7 @@ const PPB_ImageData g_ppb_image_data_thunk = {
 
 }  // namespace
 
-const PPB_ImageData* GetPPB_ImageData_Thunk() {
+const PPB_ImageData_1_0* GetPPB_ImageData_1_0_Thunk() {
   return &g_ppb_image_data_thunk;
 }