Only dispatch menu events if they have a valid target.

ui/events/event_utils.cc

Index: ui/events/event_utils.cc
diff --git a/ui/events/event_utils.cc b/ui/events/event_utils.cc
index e5a319e10f15bf0daab6633f98588eb86fd0b272..e4b384a47442200a13e29deb7aefadd74ba297a4 100644
--- a/ui/events/event_utils.cc
+++ b/ui/events/event_utils.cc
@@ -16,6 +16,53 @@ namespace {
 int g_custom_event_types = ET_LAST;
 }  // namespace
 
+scoped_ptr<Event> EventFromNative(const base::NativeEvent& native_event) {
+  scoped_ptr<Event> event;
+  EventType type = EventTypeFromNative(native_event);
+  switch(type) {
+    case ET_KEY_PRESSED:
+    case ET_KEY_RELEASED:
+      event.reset(new KeyEvent(native_event, false));
+      break;
+
+    case ET_TRANSLATED_KEY_PRESS:
+    case ET_TRANSLATED_KEY_RELEASE:
+      // These should not be generated by native events.
+      NOTREACHED();
+      break;
+
+    case ET_MOUSE_PRESSED:
+    case ET_MOUSE_DRAGGED:
+    case ET_MOUSE_RELEASED:
+    case ET_MOUSE_MOVED:
+    case ET_MOUSE_ENTERED:
+    case ET_MOUSE_EXITED:
+      event.reset(new MouseEvent(native_event));
+      break;
+
+    case ET_MOUSEWHEEL:
+      event.reset(new MouseWheelEvent(native_event));
+      break;
+
+    case ET_SCROLL_FLING_START:
+    case ET_SCROLL_FLING_CANCEL:
+    case ET_SCROLL:
+      event.reset(new ScrollEvent(native_event));
+      break;
+
+    case ET_TOUCH_RELEASED:
+    case ET_TOUCH_PRESSED:
+    case ET_TOUCH_MOVED:
+    case ET_TOUCH_CANCELLED:
+      event.reset(new TouchEvent(native_event));
+      break;
+
+    default:
+      break;
+  }
+  return event.Pass();
+}
+
 int RegisterCustomEventType() {
   return ++g_custom_event_types;
 }