Adding GetEventSource() method to the WindowTreeHost class.

ui/aura/window_tree_host_ozone.cc

 // Copyright 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_tree_host_ozone.h"
 
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/cursor/ozone/cursor_factory_ozone.h"
 #include "ui/events/ozone/event_factory_ozone.h"
 #include "ui/events/platform/platform_event_source.h"
@@ skipping 33 matching lines @@
     return bounds_.Contains(static_cast<ui::LocatedEvent*>(event)->location());
   return true;
 }
 
 uint32_t WindowTreeHostOzone::DispatchEvent(const ui::PlatformEvent& ne) {
   ui::Event* event = static_cast<ui::Event*>(ne);
   ui::EventDispatchDetails details ALLOW_UNUSED = SendEventToProcessor(event);
   return ui::POST_DISPATCH_STOP_PROPAGATION;
 }
 
+ui::EventSource* WindowTreeHostOzone::GetEventSource() {
+  return this;
+}
+
 gfx::AcceleratedWidget WindowTreeHostOzone::GetAcceleratedWidget() {
   return widget_;
 }
 
 void WindowTreeHostOzone::Show() { NOTIMPLEMENTED(); }
 
 void WindowTreeHostOzone::Hide() { NOTIMPLEMENTED(); }
 
 gfx::Rect WindowTreeHostOzone::GetBounds() const { return bounds_; }
 
@@ skipping 53 matching lines @@
   return new WindowTreeHostOzone(bounds);
 }
 
 // static
 gfx::Size WindowTreeHost::GetNativeScreenSize() {
   NOTIMPLEMENTED();
   return gfx::Size();
 }
 
 }  // namespace aura