Setup DiscardableMemory in the ash process

ui/aura/mus/window_tree_client.h

 // Copyright 2014 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_MUS_WINDOW_TREE_CLIENT_H_
 #define UI_AURA_MUS_WINDOW_TREE_CLIENT_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 12 matching lines @@
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/client/transient_window_client_observer.h"
 #include "ui/aura/mus/capture_synchronizer_delegate.h"
 #include "ui/aura/mus/drag_drop_controller_host.h"
 #include "ui/aura/mus/focus_synchronizer_delegate.h"
 #include "ui/aura/mus/mus_types.h"
 #include "ui/aura/mus/window_manager_delegate.h"
 #include "ui/aura/mus/window_tree_host_mus_delegate.h"
 
+namespace base {
+class Thread;
+}
+
+namespace discardable_memory {
+class ClientDiscardableSharedMemoryManager;
+}
+
 namespace display {
 class Display;
 }
 
 namespace gfx {
 class Insets;
 }
 
 namespace service_manager {
 class Connector;
@@ skipping 493 matching lines @@
   base::Callback<void(bool)> on_current_move_finished_;
 
   // The current change id for the window manager.
   uint32_t current_wm_move_loop_change_ = 0u;
   Id current_wm_move_loop_window_id_ = 0u;
 
   std::unique_ptr<DragDropControllerMus> drag_drop_controller_;
 
   base::ObserverList<WindowTreeClientTestObserver> test_observers_;
 
+  // IO thread for GPU and discardable shared memory IPC.
+  std::unique_ptr<base::Thread> io_thread_;
+
   std::unique_ptr<ui::Gpu> gpu_;
   std::unique_ptr<MusContextFactory> compositor_context_factory_;
 
+  std::unique_ptr<discardable_memory::ClientDiscardableSharedMemoryManager>
+      discardable_shared_memory_manager_;
+
   // If |compositor_context_factory_| is installed on Env, then this is the
   // ContextFactory that was set on Env originally.
   ui::ContextFactory* initial_context_factory_ = nullptr;
   base::WeakPtrFactory<WindowTreeClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeClient);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_TREE_CLIENT_H_