Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 11114f9c04d007dc7c4309a23b43230135fbfedd..64a67ba134d2a541804a355f55d7498b7d14b45f 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -13361,6 +13361,10 @@ Handle<String> JSFunction::ToString(Handle<JSFunction> function) {
     return NativeCodeFunctionSourceString(shared_info);
   }
 
+  if (FLAG_harmony_function_tostring) {
+    return Handle<String>::cast(shared_info->GetSourceCodeHarmony());
+  }
+
   IncrementalStringBuilder builder(isolate);
   FunctionKind kind = shared_info->kind();
   if (!IsArrowFunction(kind)) {
@@ -13799,6 +13803,15 @@ Handle<Object> SharedFunctionInfo::GetSourceCode() {
       source, start_position(), end_position());
 }
 
+Handle<Object> SharedFunctionInfo::GetSourceCodeHarmony() {
+  Isolate* isolate = GetIsolate();
+  if (!HasSourceCode()) return isolate->factory()->undefined_value();
+  Handle<String> script_source(String::cast(Script::cast(script())->source()));
+  int start_pos = function_token_position();
+  if (start_pos == kNoSourcePosition) start_pos = start_position();
+  return isolate->factory()->NewSubString(script_source, start_pos,
+                                          end_position());
+}
 
 bool SharedFunctionInfo::IsInlineable() {
   // Check that the function has a script associated with it.