Introduce v8::Exception::GetMessage to find location of an error object.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 6a7c40a06c96cc3246fde4c52f4cf94657e836da..2f79e9f21e3772c8944416561360c3e60d6adef3 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -6961,6 +6961,17 @@ DEFINE_ERROR(Error)
 #undef DEFINE_ERROR
 
 
+Local<Message> Exception::GetMessage(Handle<Value> exception) {
+  i::Handle<i::Object> obj = Utils::OpenHandle(*exception);
+  if (!obj->IsHeapObject()) return Local<Message>();
+  i::Isolate* isolate = i::HeapObject::cast(*obj)->GetIsolate();
+  ENTER_V8(isolate);
+  i::HandleScope scope(isolate);
+  return Utils::MessageToLocal(
+      scope.CloseAndEscape(isolate->CreateMessage(obj, NULL)));
+}
+
+
 Local<StackTrace> Exception::GetStackTrace(Handle<Value> exception) {
   i::Handle<i::Object> obj = Utils::OpenHandle(*exception);
   if (!obj->IsJSObject()) return Local<StackTrace>();