ES6 symbols: Allow symbols as property names

src/objects-printer.cc

Index: src/objects-printer.cc
diff --git a/src/objects-printer.cc b/src/objects-printer.cc
index 471afc9c37b8bc34af5ebf4b0ff9d6721a044ef2..a9c94ddae98e97394398e350ea4ec6572f6b3ed0 100644
--- a/src/objects-printer.cc
+++ b/src/objects-printer.cc
@@ -259,7 +259,7 @@ void JSObject::PrintProperties(FILE* out) {
     DescriptorArray* descs = map()->instance_descriptors();
     for (int i = 0; i < map()->NumberOfOwnDescriptors(); i++) {
       PrintF(out, "   ");
-      descs->GetKey(i)->StringPrint(out);
+      descs->GetKey(i)->NamePrint(out);
       PrintF(out, ": ");
       switch (descs->GetType(i)) {
         case FIELD: {
@@ -417,7 +417,7 @@ void JSObject::PrintTransitions(FILE* out) {
   TransitionArray* transitions = map()->transitions();
   for (int i = 0; i < transitions->number_of_transitions(); i++) {
     PrintF(out, "   ");
-    transitions->GetKey(i)->StringPrint(out);
+    transitions->GetKey(i)->NamePrint(out);
     PrintF(out, ": ");
     switch (transitions->GetTargetDetails(i).type()) {
       case FIELD: {
@@ -710,6 +710,14 @@ void String::StringPrint(FILE* out) {
 }
 
 
+void Name::NamePrint(FILE* out) {
+  if (IsString())
+    String::cast(this)->StringPrint(out);
+  else
+    ShortPrint();
+}
+
+
 // This method is only meant to be called from gdb for debugging purposes.
 // Since the string can also be in two-byte encoding, non-ASCII characters
 // will be ignored in the output.
@@ -1107,7 +1115,7 @@ void TransitionArray::PrintTransitions(FILE* out) {
   PrintF(out, "Transition array  %d\n", number_of_transitions());
   for (int i = 0; i < number_of_transitions(); i++) {
     PrintF(out, " %d: ", i);
-    GetKey(i)->StringPrint(out);
+    GetKey(i)->NamePrint(out);
     PrintF(out, ": ");
     switch (GetTargetDetails(i).type()) {
       case FIELD: {