Implement for-in loop for proxies.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index a03b7411c3cdf7b9cef5722a393a726ff62b5905..acab9d86f58cc977c13a961015e7c429fbf17a28 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -2874,8 +2874,10 @@ Local<Array> v8::Object::GetPropertyNames() {
   ENTER_V8(isolate);
   i::HandleScope scope(isolate);
   i::Handle<i::JSObject> self = Utils::OpenHandle(this);
+  bool threw = false;
   i::Handle<i::FixedArray> value =
-      i::GetKeysInFixedArrayFor(self, i::INCLUDE_PROTOS);
+      i::GetKeysInFixedArrayFor(self, i::INCLUDE_PROTOS, &threw);
+  if (threw) return Local<v8::Array>();
   // Because we use caching to speed up enumeration it is important
   // to never change the result of the basic enumeration function so
   // we clone the result.
@@ -2893,8 +2895,10 @@ Local<Array> v8::Object::GetOwnPropertyNames() {
   ENTER_V8(isolate);
   i::HandleScope scope(isolate);
   i::Handle<i::JSObject> self = Utils::OpenHandle(this);
+  bool threw = false;
   i::Handle<i::FixedArray> value =
-      i::GetKeysInFixedArrayFor(self, i::LOCAL_ONLY);
+      i::GetKeysInFixedArrayFor(self, i::LOCAL_ONLY, &threw);
+  if (threw) return Local<v8::Array>();
   // Because we use caching to speed up enumeration it is important
   // to never change the result of the basic enumeration function so
   // we clone the result.