Do not set the last mouse location from synthesized event

ui/aura/test/event_generator.cc

Index: ui/aura/test/event_generator.cc
diff --git a/ui/aura/test/event_generator.cc b/ui/aura/test/event_generator.cc
index e914a77a72547b08132422f8066c827bd1cecd6c..4926454a54f9096283b564d4053dfc22702d3fcb 100644
--- a/ui/aura/test/event_generator.cc
+++ b/ui/aura/test/event_generator.cc
@@ -596,7 +596,7 @@ void EventGenerator::DoDispatchEvent(ui::Event* event, bool async) {
     pending_events_.push_back(pending_event);
   } else {
     ui::EventDispatchDetails details = current_root_window_->OnEventFromSource(
-        static_cast<ui::KeyEvent*>(event));
+        event);
     CHECK(!details.dispatcher_destroyed);
   }
 }