Setup DiscardableMemory in the ash process

ash/mus/window_manager_application.h

Index: ash/mus/window_manager_application.h
diff --git a/ash/mus/window_manager_application.h b/ash/mus/window_manager_application.h
index 757e24bc4e71d7370343f23d415aace4e32de9b9..ea5b48833706ad9ba9c6e0b1c705b998ee6a0f9e 100644
--- a/ash/mus/window_manager_application.h
+++ b/ash/mus/window_manager_application.h
@@ -24,6 +24,7 @@ class WindowTreeClient;
 
 namespace base {
 class SequencedWorkerPool;
+class Thread;
 }
 
 namespace chromeos {
@@ -32,6 +33,10 @@ class ScopedFakeStatisticsProvider;
 }
 }
 
+namespace discardable_memory {
+class ClientDiscardableSharedMemoryManager;
+}
+
 namespace views {
 class AuraInit;
 }
@@ -73,6 +78,8 @@ class WindowManagerApplication : public service_manager::Service {
 
   tracing::Provider tracing_;
 
+  std::unique_ptr<base::Thread> io_thread_;
+
   std::unique_ptr<views::AuraInit> aura_init_;
 
   std::unique_ptr<WindowManager> window_manager_;
@@ -83,6 +90,8 @@ class WindowManagerApplication : public service_manager::Service {
   std::unique_ptr<NetworkConnectDelegateMus> network_connect_delegate_;
   std::unique_ptr<chromeos::system::ScopedFakeStatisticsProvider>
       statistics_provider_;
+  std::unique_ptr<discardable_memory::ClientDiscardableSharedMemoryManager>
+      discardable_shared_memory_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManagerApplication);
 };