Setup DiscardableMemory in the ash process

ui/views/mus/mus_client.h

Index: ui/views/mus/mus_client.h
diff --git a/ui/views/mus/mus_client.h b/ui/views/mus/mus_client.h
index 781edb57f7ab9c708ae06b04f21c5c32edb0e4f8..42e1ac5596b8fe09ddc9de79319ffc65e471895e 100644
--- a/ui/views/mus/mus_client.h
+++ b/ui/views/mus/mus_client.h
@@ -30,10 +30,6 @@ class SingleThreadTaskRunner;
 class Thread;
 }
 
-namespace discardable_memory {
-class ClientDiscardableSharedMemoryManager;
-}
-
 namespace service_manager {
 class Connector;
 }
@@ -161,9 +157,6 @@ class VIEWS_MUS_EXPORT MusClient : public aura::WindowTreeClientDelegate,
 
   std::unique_ptr<PointerWatcherEventRouter> pointer_watcher_event_router_;
 
-  std::unique_ptr<discardable_memory::ClientDiscardableSharedMemoryManager>
-      discardable_shared_memory_manager_;
-
   DISALLOW_COPY_AND_ASSIGN(MusClient);
 };