[esnext] implement frontend changes for async/await proposal

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index 92b02071add0747ea5d76853fb2108b15ccf9edd..90e933f0ba874bd698d8fdeb873a557d78b37f0c 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -445,13 +445,13 @@ class PreParserFactory {
   PreParserExpression NewObjectLiteralProperty(PreParserExpression key,
                                                PreParserExpression value,
                                                ObjectLiteralProperty::Kind kind,
-                                               bool is_static,
+                                               MethodKind method_kind,
                                                bool is_computed_name) {
     return PreParserExpression::Default();
   }
   PreParserExpression NewObjectLiteralProperty(PreParserExpression key,
                                                PreParserExpression value,
-                                               bool is_static,
+                                               MethodKind method_kind,
                                                bool is_computed_name) {
     return PreParserExpression::Default();
   }
@@ -622,6 +622,10 @@ class PreParserTraits {
     return identifier.IsArguments();
   }
 
+  static bool IsAwait(PreParserIdentifier identifier) {
+    return identifier.IsAwait();
+  }
+
   static bool IsEvalOrArguments(PreParserIdentifier identifier) {
     return identifier.IsEvalOrArguments();
   }
@@ -865,6 +869,8 @@ class PreParserTraits {
       PreParserExpression expression, const Scanner::Location& params_loc,
       Scanner::Location* duplicate_loc, bool* ok);
 
+  V8_INLINE PreParserExpression ParseAsyncFunctionExpression(bool* ok);
+
   void ReindexLiterals(const PreParserFormalParameters& paramaters) {}
 
   struct TemplateLiteralState {};
@@ -937,6 +943,11 @@ class PreParserTraits {
                                            PreParserExpressionList args,
                                            int pos);
 
+  inline PreParserExpression ExpressionListToExpression(
+      PreParserExpressionList args) {
+    return PreParserExpression::Default();
+  }
+
   inline void RewriteDestructuringAssignments() {}
 
   inline PreParserExpression RewriteExponentiation(PreParserExpression left,
@@ -960,6 +971,9 @@ class PreParserTraits {
   inline void RewriteNonPattern(Type::ExpressionClassifier* classifier,
                                 bool* ok);
 
+  inline PreParserExpression RewriteAwaitExpression(PreParserExpression value,
+                                                    int pos);
+
   V8_INLINE Zone* zone() const;
   V8_INLINE ZoneList<PreParserExpression>* GetNonPatternList() const;
 
@@ -1078,6 +1092,8 @@ class PreParser : public ParserBase<PreParserTraits> {
   Statement ParseHoistableDeclaration(bool* ok);
   Statement ParseHoistableDeclaration(int pos, bool is_generator, bool* ok);
   Statement ParseFunctionDeclaration(bool* ok);
+  Statement ParseAsyncFunctionDeclaration(bool* ok);
+  Expression ParseAsyncFunctionExpression(bool* ok);
   Statement ParseClassDeclaration(bool* ok);
   Statement ParseBlock(bool* ok);
   Statement ParseVariableStatement(VariableDeclarationContext var_context,
@@ -1166,6 +1182,9 @@ void PreParserTraits::ParseArrowFunctionFormalParameterList(
   // lists that are too long.
 }
 
+PreParserExpression PreParserTraits::ParseAsyncFunctionExpression(bool* ok) {
+  return pre_parser_->ParseAsyncFunctionExpression(ok);
+}
 
 PreParserExpression PreParserTraits::ParseDoExpression(bool* ok) {
   return pre_parser_->ParseDoExpression(ok);
@@ -1177,6 +1196,10 @@ void PreParserTraits::RewriteNonPattern(Type::ExpressionClassifier* classifier,
   pre_parser_->ValidateExpression(classifier, ok);
 }
 
+PreParserExpression PreParserTraits::RewriteAwaitExpression(
+    PreParserExpression value, int pos) {
+  return value;
+}
 
 Zone* PreParserTraits::zone() const {
   return pre_parser_->function_state_->scope()->zone();