Add responsive and unresponsive events for window.

browser/api/atom_api_window.cc

@@ -71,6 +71,14 @@ void Window::OnWindowBlur() {
   Emit("blur");
 }
 
+void Window::OnRendererUnresponsive() {
+  Emit("unresponsive");
+}
+
+void Window::OnRendererResponsive() {
+  Emit("responsive");
+}
+
 // static
 v8::Handle<v8::Value> Window::New(const v8::Arguments &args) {
   v8::HandleScope scope;