Introduce extended mode.

src/preparser.h

Index: src/preparser.h
diff --git a/src/preparser.h b/src/preparser.h
index 647a142b1a152d31fe059fbd72224450bca9d3b5..fbc852e3fd2101dc689c077b12fb10c43fd7dac7 100644
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -417,8 +417,8 @@ class PreParser {
           materialized_literal_count_(0),
           expected_properties_(0),
           with_nesting_count_(0),
-          strict_mode_flag_((prev_ != NULL) ? prev_->strict_mode_flag()
-                            : i::kNonStrictMode) {
+          language_mode_(
+              (prev_ != NULL) ? prev_->language_mode() : i::CLASSIC_MODE) {
       *variable = this;
     }
     ~Scope() { *variable_ = prev_; }
@@ -428,12 +428,14 @@ class PreParser {
     int expected_properties() { return expected_properties_; }
     int materialized_literal_count() { return materialized_literal_count_; }
     bool IsInsideWith() { return with_nesting_count_ != 0; }
-    bool is_strict_mode() { return strict_mode_flag_ == i::kStrictMode; }
-    i::StrictModeFlag strict_mode_flag() {
-      return strict_mode_flag_;
+    bool is_classic_mode() {
+      return language_mode_ == i::CLASSIC_MODE;
     }
-    void set_strict_mode_flag(i::StrictModeFlag strict_mode_flag) {
-      strict_mode_flag_ = strict_mode_flag;
+    i::LanguageMode language_mode() {
+      return language_mode_;
+    }
+    void set_language_mode(i::LanguageMode language_mode) {
+      language_mode_ = language_mode;
     }
     void EnterWith() { with_nesting_count_++; }
     void LeaveWith() { with_nesting_count_--; }
@@ -445,7 +447,7 @@ class PreParser {
     int materialized_literal_count_;
     int expected_properties_;
     int with_nesting_count_;
-    i::StrictModeFlag strict_mode_flag_;
+    i::LanguageMode language_mode_;
   };
 
   // Private constructor only used in PreParseProgram.
@@ -476,7 +478,7 @@ class PreParser {
     if (stack_overflow_) return kPreParseStackOverflow;
     if (!ok) {
       ReportUnexpectedToken(scanner_->current_token());
-    } else if (scope_->is_strict_mode()) {
+    } else if (!scope_->is_classic_mode()) {
       CheckOctalLiteral(start_position, scanner_->location().end_pos, &ok);
     }
     return kPreParseSuccess;
@@ -580,13 +582,19 @@ class PreParser {
 
   bool peek_any_identifier();
 
-  void set_strict_mode() {
-    scope_->set_strict_mode_flag(i::kStrictMode);
+  void set_language_mode(i::LanguageMode language_mode) {
+    scope_->set_language_mode(language_mode);
+  }
+
+  bool is_classic_mode() {
+    return scope_->language_mode() == i::CLASSIC_MODE;
   }
 
-  bool strict_mode() { return scope_->strict_mode_flag() == i::kStrictMode; }
+  bool is_extended_mode() {
+    return scope_->language_mode() == i::EXTENDED_MODE;
+  }
 
-  i::StrictModeFlag strict_mode_flag() { return scope_->strict_mode_flag(); }
+  i::LanguageMode language_mode() { return scope_->language_mode(); }
 
   void Consume(i::Token::Value token) { Next(); }