Add initial parser support for harmony iteration

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index eea617f8dc0d1d1e82e86cd4746e4eaad84d1acb..ae600d6753e0b974639952deb96619fe9b0d6738 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -437,6 +437,7 @@ class Parser BASE_EMBEDDED {
   bool allow_modules() { return scanner().HarmonyModules(); }
   bool allow_harmony_scoping() { return scanner().HarmonyScoping(); }
   bool allow_generators() const { return allow_generators_; }
+  bool allow_for_of() const { return allow_for_of_; }
 
   void set_allow_natives_syntax(bool allow) { allow_natives_syntax_ = allow; }
   void set_allow_lazy(bool allow) { allow_lazy_ = allow; }
@@ -445,6 +446,7 @@ class Parser BASE_EMBEDDED {
     scanner().SetHarmonyScoping(allow);
   }
   void set_allow_generators(bool allow) { allow_generators_ = allow; }
+  void set_allow_for_of(bool allow) { allow_for_of_ = allow; }
 
   // Parses the source code represented by the compilation info and sets its
   // function literal.  Returns false (and deallocates any allocated AST
@@ -721,13 +723,16 @@ class Parser BASE_EMBEDDED {
 
   bool is_generator() const { return current_function_state_->is_generator(); }
 
+  bool CheckInOrOf(ForEachStatement::VisitMode* visit_mode);
+
   bool peek_any_identifier();
 
   INLINE(void Consume(Token::Value token));
   void Expect(Token::Value token, bool* ok);
   bool Check(Token::Value token);
   void ExpectSemicolon(bool* ok);
-  void ExpectContextualKeyword(const char* keyword, bool* ok);
+  bool CheckContextualKeyword(Vector<const char> keyword);
+  void ExpectContextualKeyword(Vector<const char> keyword, bool* ok);
 
   Handle<String> LiteralString(PretenureFlag tenured) {
     if (scanner().is_literal_ascii()) {
@@ -850,6 +855,7 @@ class Parser BASE_EMBEDDED {
   bool allow_natives_syntax_;
   bool allow_lazy_;
   bool allow_generators_;
+  bool allow_for_of_;
   bool stack_overflow_;
   // If true, the next (and immediately following) function literal is
   // preceded by a parenthesis.