Make the parser track the language mode instead of keeping its own harmony flag.

src/compiler.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 464 matching lines @@
     // saving if we might skip building the AST for lazily compiled functions.
     // I.e., preparse data isn't relevant when the lazy flag is off, and
     // for small sources, odds are that there aren't many functions
     // that would be compiled lazily anyway, so we skip the preparse step
     // in that case too.
     ScriptDataImpl* pre_data = input_pre_data;
     int flags = kNoParsingFlags;
     if ((natives == NATIVES_CODE) || FLAG_allow_natives_syntax) {
       flags |= kAllowNativesSyntax;
     }
-    if (natives != NATIVES_CODE && FLAG_harmony_scoping) {
-      flags |= kHarmonyScoping;
-    }
     if (pre_data == NULL
         && source_length >= FLAG_min_preparse_length) {
       if (source->IsExternalTwoByteString()) {
         ExternalTwoByteStringUC16CharacterStream stream(
             Handle<ExternalTwoByteString>::cast(source), 0, source->length());
         pre_data = ParserApi::PartialPreParse(&stream, extension, flags);
       } else {
         GenericStringUC16CharacterStream stream(source, 0, source->length());
         pre_data = ParserApi::PartialPreParse(&stream, extension, flags);
       }
@@ skipping 290 matching lines @@
     }
   }
 
   GDBJIT(AddCode(Handle<String>(shared->DebugName()),
                  Handle<Script>(info->script()),
                  Handle<Code>(info->code()),
                  info));
 }
 
 } }  // namespace v8::internal