Move ErrorToString to runtime

src/runtime/runtime-error.cc

Index: src/runtime/runtime-error.cc
diff --git a/src/runtime/runtime-error.cc b/src/runtime/runtime-error.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3a9b19202990f486511b164c0a5141c70be5f467
--- /dev/null
+++ b/src/runtime/runtime-error.cc
@@ -0,0 +1,24 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/runtime/runtime-utils.h"
+
+#include "src/arguments.h"
+#include "src/base/platform/time.h"
+#include "src/conversions-inl.h"
+#include "src/futex-emulation.h"
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+RUNTIME_FUNCTION(Runtime_ErrorToString) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, recv, 0);
+  RETURN_RESULT_OR_FAILURE(isolate, ErrorUtils::ToString(isolate, recv));
+}
+
+}  // namespace internal
+}  // namespace v8