Introduce extended mode.

src/ast.h

 // 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 1671 matching lines @@
 
   Handle<String> name() const { return name_; }
   Scope* scope() const { return scope_; }
   ZoneList<Statement*>* body() const { return body_; }
   void set_function_token_position(int pos) { function_token_position_ = pos; }
   int function_token_position() const { return function_token_position_; }
   int start_position() const;
   int end_position() const;
   bool is_expression() const { return IsExpression::decode(bitfield_); }
   bool is_anonymous() const { return IsAnonymous::decode(bitfield_); }
-  bool strict_mode() const { return strict_mode_flag() == kStrictMode; }
-  StrictModeFlag strict_mode_flag() const;
+  bool is_classic_mode() const { return language_mode() == CLASSIC_MODE; }
+  LanguageMode language_mode() const;
 
   int materialized_literal_count() { return materialized_literal_count_; }
   int expected_property_count() { return expected_property_count_; }
   int handler_count() { return handler_count_; }
   bool has_only_simple_this_property_assignments() {
     return HasOnlySimpleThisPropertyAssignments::decode(bitfield_);
   }
   Handle<FixedArray> this_property_assignments() {
       return this_property_assignments_;
   }
@@ skipping 463 matching lines @@
 
  private:
   Isolate* isolate_;
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_