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 829a04997f4cdd5a2805c80fa921c64c35820943..cb8424a1d2f13d1968a326a18ebc8b917691fd74 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;
 }
@@ -153,9 +149,6 @@ 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);
 };