Mark the ET_MOUSE_MOVED created from a pointer grab as synthesized.

ui/aura/env_input_state_controller.cc

Index: ui/aura/env_input_state_controller.cc
diff --git a/ui/aura/env_input_state_controller.cc b/ui/aura/env_input_state_controller.cc
index 7e3b2916174e83790e28939fcaf8af62bde6c631..6807055790b1044d7a344d7e4fb648fca67ff36a 100644
--- a/ui/aura/env_input_state_controller.cc
+++ b/ui/aura/env_input_state_controller.cc
@@ -26,8 +26,11 @@ void EnvInputStateController::UpdateStateForMouseEvent(
       break;
   }
 
+  // If a synthesized event is created from a native event (e.g. EnterNotify
+  // XEvents), then we should take the location as we would for a
+  // non-synthesized event.
   if (event.type() != ui::ET_MOUSE_CAPTURE_CHANGED &&
-      !(event.flags() & ui::EF_IS_SYNTHESIZED)) {
+      (!(event.flags() & ui::EF_IS_SYNTHESIZED) || event.HasNativeEvent())) {
     SetLastMouseLocation(window, event.root_location());
   }
 }