Construct and check for mojo::Event's LocationData as needed.

components/mus/event_dispatcher.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/mus/event_dispatcher.h"
 
 #include "components/mus/server_view.h"
 #include "components/mus/view_coordinate_conversions.h"
 #include "components/mus/view_locator.h"
 #include "components/mus/view_tree_host_impl.h"
@@ skipping 53 matching lines @@
         pair.second.flags == event.flags) {
       *accelerator_id = pair.first;
       return true;
     }
   }
   return false;
 }
 
 ServerView* EventDispatcher::FindEventTarget(mojo::Event* event) {
   ServerView* focused_view = view_tree_host_->GetFocusedView();
-  if (event->pointer_data) {
+  if (event->pointer_data && event->pointer_data->location) {
     ServerView* root = view_tree_host_->root_view();
     const gfx::Point root_point(
         static_cast<int>(event->pointer_data->location->x),
         static_cast<int>(event->pointer_data->location->y));
     ServerView* target = focused_view;
     if (event->action == mojo::EVENT_TYPE_POINTER_DOWN || !target ||
         !root->Contains(target)) {
       target = FindDeepestVisibleView(root, root_point);
       CHECK(target);
     }
     const gfx::PointF local_point(ConvertPointFBetweenViews(
         root, target, gfx::PointF(event->pointer_data->location->x,
                                   event->pointer_data->location->y)));
     event->pointer_data->location->x = local_point.x();
     event->pointer_data->location->y = local_point.y();
     return target;
   }
 
   return focused_view;
 }
 
 }  // namespace mus