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

ppapi/thunk/ppb_char_set_thunk.cc

Index: ppapi/thunk/ppb_char_set_thunk.cc
diff --git a/ppapi/thunk/ppb_char_set_thunk.cc b/ppapi/thunk/ppb_char_set_thunk.cc
index 27419b4a14a32de97205314954be02d78a5bf37b..4fc57ce6d523c80acc28ba7bd9ff4837676ccfd5 100644
--- a/ppapi/thunk/ppb_char_set_thunk.cc
+++ b/ppapi/thunk/ppb_char_set_thunk.cc
@@ -68,7 +68,7 @@ const PPB_CharSet_Dev g_ppb_char_set_thunk = {
 
 }  // namespace
 
-const PPB_CharSet_Dev* GetPPB_CharSet_Dev_Thunk() {
+const PPB_CharSet_Dev_0_4* GetPPB_CharSet_Dev_0_4_Thunk() {
   return &g_ppb_char_set_thunk;
 }