Fix X11DesktopHandler::ActivateWindow on Unity for known user gestures

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index c82ced73bb74b4175c43a6b5da51e8dc80031b95..dc64ce4b88cfcbabd0e92d38ed443ef729915710 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -788,6 +788,11 @@ void DesktopNativeWidgetAura::Activate() {
     desktop_window_tree_host_->Activate();
 }
 
+void DesktopNativeWidgetAura::ActivateForUserGesture() {
+  if (content_window_)
+    desktop_window_tree_host_->ActivateForUserGesture();
+}
+
 void DesktopNativeWidgetAura::Deactivate() {
   if (content_window_)
     desktop_window_tree_host_->Deactivate();