Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index 41fb11124b6866a00f65fd0318e38139daeea09c..d00b7db9d48a87ef4d2cb49089f267221afd5fec 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -1124,6 +1124,12 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
     ++use_counts_[feature];
   }
 
+  // Returns true iff we're parsing the first function literal during
+  // CreateDynamicFunction().
+  V8_INLINE bool IgnoreFunctionName() const {

[Dan Ehrenberg, 2016/12/06 00:32:13]

Naming nit: How about something that's more about what this signifies, rather
than what it's used for? Such as, IsDynamicFunction()

[jwolfe, 2017/01/13 00:28:48]

How about ParsingDynamicFunctionDeclaration? The semantics are a bit strange,
because the return value becomes false after the parameters are done being
parsed. This is so that it doesn't affect any functions declared inside the
dynamic function. So I think some extra words in the name are justified to match
the non-trivial behavior, but I know I disagree on this kind of thing with
people quite often, so I'm still open to other naming ideas.

+    return parameters_end_pos_ != kNoSourcePosition;
+  }
+
   // Parser's private field members.
   friend class DiscardableZoneScope;  // Uses reusable_preparser_.
   // FIXME(marja): Make reusable_preparser_ always use its own temp Zone (call
@@ -1150,6 +1156,12 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
   bool allow_lazy_;
   bool temp_zoned_;
   ParserLogger* log_;
+
+  // If not kNoSourcePosition, indicates that the first function literal
+  // encountered is a dynamic function, see CreateDynamicFunction(). This field
+  // indicates the correct position of the ')' that closes the parameter list.
+  // After that ')' is encountered, this field is reset to kNoSourcePosition.
+  int parameters_end_pos_;
 };
 
 // ----------------------------------------------------------------------------