Make ui::test::EventGenerator work with PointerEvents in mash

ui/aura/env.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_AURA_ENV_H_
 #define UI_AURA_ENV_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 129 matching lines @@
   ui::EventTarget* GetParentTarget() override;
   std::unique_ptr<ui::EventTargetIterator> GetChildIterator() const override;
   ui::EventTargeter* GetEventTargeter() override;
 
   // Overridden from ui::OSExchangeDataProviderFactory::Factory:
   std::unique_ptr<ui::OSExchangeData::Provider> BuildProvider() override;
 
   // This is not const for tests, which may share Env across tests and so needs
   // to reset the value.
   Mode mode_;
+
+  // Intentionally not exposed publicly. Someday we might want to support
+  // multiple WindowTreeClients. Use EnvTestHelper in tests.
   WindowTreeClient* window_tree_client_ = nullptr;
 
   base::ObserverList<EnvObserver> observers_;
 
   int mouse_button_flags_;
   // Location of last mouse event, in screen coordinates.
   mutable gfx::Point last_mouse_location_;
   bool is_touch_down_;
   bool get_last_mouse_location_from_mus_;
   // This may be set to true in tests to force using |last_mouse_location_|
@@ skipping 10 matching lines @@
   client::FocusClient* active_focus_client_ = nullptr;
   std::unique_ptr<ActiveFocusClientWindowObserver>
       active_focus_client_window_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(Env);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ENV_H_