Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/parsing/parser.cc

Index: src/parsing/parser.cc
diff --git a/src/parsing/parser.cc b/src/parsing/parser.cc
index 0c0fdf08d669470010869e078897bf6eec443175..384f2ed0dc319d386ba0176bf76c2a69aa0a3b2f 100644
--- a/src/parsing/parser.cc
+++ b/src/parsing/parser.cc
@@ -596,6 +596,7 @@ Parser::Parser(ParseInfo* info)
       compile_options_(info->compile_options()),
       cached_parse_data_(nullptr),
       total_preparse_skipped_(0),
+      parameters_end_pos_(info->parameters_end_pos()),
       parsing_on_main_thread_(true) {
   // Even though we were passed ParseInfo, we should not store it in
   // Parser - this makes sure that Isolate is not accidentally accessed via
@@ -2530,6 +2531,14 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
                                                     : function_token_pos;
 
   bool is_generator = IsGeneratorFunction(kind);
+  int expected_parameters_end_pos = parameters_end_pos_;
+  if (expected_parameters_end_pos != kNoSourcePosition) {
+    // This is the first function literal encountered in an only-single-function
+    // eval.
+    parameters_end_pos_ = kNoSourcePosition;
+    // The function name should have been ignored, giving us null here.
+    DCHECK_NULL(function_name);
+  }
 
   // Anonymous functions were passed either the empty symbol or a null
   // handle as the function name.  Remember if we were passed a non-empty
@@ -2642,6 +2651,17 @@ FunctionLiteral* Parser::ParseFunctionLiteral(
   this->scope()->set_start_position(start_position);
   ParserFormalParameters formals(scope);
   ParseFormalParameterList(&formals, CHECK_OK);
+  if (expected_parameters_end_pos != kNoSourcePosition) {
+    // Check for '(' or ')' shenanigans in the parameter string for dynamic
+    // functions.
+    if (peek_position() != expected_parameters_end_pos) {
+      ReportMessageAt(Scanner::Location(expected_parameters_end_pos,
+                                        expected_parameters_end_pos + 1),
+                      MessageTemplate::kExpectedEndOfParameters);
+      *ok = false;
+      return nullptr;
+    }
+  }
   Expect(Token::RPAREN, CHECK_OK);
   int formals_end_position = scanner()->location().end_pos;