Fix sticky keys crash when handling synthetic events without a native event.

ash/sticky_keys/sticky_keys_controller.cc

Index: ash/sticky_keys/sticky_keys_controller.cc
diff --git a/ash/sticky_keys/sticky_keys_controller.cc b/ash/sticky_keys/sticky_keys_controller.cc
index e5bb0afe2483c32c1dbd4a20dfff9f6583cf4c8b..45c1248567614e7062aa0e0d135adb9b544fb82d 100644
--- a/ash/sticky_keys/sticky_keys_controller.cc
+++ b/ash/sticky_keys/sticky_keys_controller.cc
@@ -69,10 +69,18 @@ void StickyKeysHandlerDelegateImpl::DispatchMouseEvent(ui::MouseEvent* event,
   DCHECK(target);
   // We need to send a new, untransformed mouse event to the host.
   if (event->IsMouseWheelEvent()) {
-    ui::MouseWheelEvent new_event(event->native_event());
+    aura::Window* source = static_cast<aura::Window*>(event->target());
+    ui::MouseWheelEvent new_event(*static_cast<ui::MouseWheelEvent*>(event),
+                                  source,
+                                  source->GetRootWindow());
+    // Transform the location back to host coordinates before dispatching.
+    new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
     DispatchEvent(&new_event, target);
   } else {
-    ui::MouseEvent new_event(event->native_event());
+    aura::Window* source = static_cast<aura::Window*>(event->target());
+    ui::MouseEvent new_event(*event, source, source->GetRootWindow());
+    // Transform the location back to host coordinates before dispatching.
+    new_event.UpdateForRootTransform(source->GetHost()->GetRootTransform());
     DispatchEvent(&new_event, target);
   }
 }