[Chromecast] Fix crash on keypress in cast_shell with Ozone X11

ui/aura/window_targeter.cc

 // Copyright (c) 2013 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 "ui/aura/window_targeter.h"
 
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/window.h"
@@ skipping 89 matching lines @@
     Window* window,
     const ui::LocatedEvent& event) {
   return SubtreeCanAcceptEvent(window, event) &&
          EventLocationInsideBounds(window, event);
 }
 
 Window* WindowTargeter::FindTargetForKeyEvent(Window* window,
                                               const ui::KeyEvent& key) {
   Window* root_window = window->GetRootWindow();
   client::FocusClient* focus_client = client::GetFocusClient(root_window);
+  if (!focus_client)
+    return window;

[sadrul, 2016/07/20 16:58:36]

Should this return nullptr?

[halliwell, 2016/07/20 17:01:42]

tbh I don't understand this code well.  But I was going by the line below, where
if the focus_client fails to GetFocusedWindow, this function will return
'window'.

   Window* focused_window = focus_client->GetFocusedWindow();
   if (!focused_window)
     return window;
 
   client::EventClient* event_client = client::GetEventClient(root_window);
   if (event_client &&
       !event_client->CanProcessEventsWithinSubtree(focused_window)) {
     focus_client->FocusWindow(nullptr);
     return nullptr;
   }
@@ skipping 68 matching lines @@
           static_cast<Window*>(targeter->FindTargetForEvent(child, event));
       if (child_target_window)
         return child_target_window;
     }
     target->ConvertEventToTarget(root_window, event);
   }
   return root_window->CanAcceptEvent(*event) ? root_window : nullptr;
 }
 
 }  // namespace aura