Fix X11DesktopHandler::ActivateWindow on Unity for known user gestures

ui/views/widget/native_widget_mac.mm

Index: ui/views/widget/native_widget_mac.mm
diff --git a/ui/views/widget/native_widget_mac.mm b/ui/views/widget/native_widget_mac.mm
index 557d498c7f6b2801432dd0142ccc5d5b42ad78df..4333cd3e9a17edc31805ba5ff58c1c27531e8646 100644
--- a/ui/views/widget/native_widget_mac.mm
+++ b/ui/views/widget/native_widget_mac.mm
@@ -374,6 +374,10 @@ void NativeWidgetMac::Activate() {
   bridge_->SetVisibilityState(BridgedNativeWidget::SHOW_AND_ACTIVATE_WINDOW);
 }
 
+void NativeWidgetMac::ActivateForUserGesture() {
+  Activate();
+}
+
 void NativeWidgetMac::Deactivate() {
   NOTIMPLEMENTED();
 }