mus: The window server needs to be able to write to the clipboard.

services/ui/service.cc

Index: services/ui/service.cc
diff --git a/services/ui/service.cc b/services/ui/service.cc
index b11c4cfed7f0b2615608c41f3e2a0065824ff804..d4eca9ccd9a5d58aa6cce8d9d4c37247d32e9ac5 100644
--- a/services/ui/service.cc
+++ b/services/ui/service.cc
@@ -75,7 +75,6 @@ struct Service::PendingRequest {
 };
 
 struct Service::UserState {
-  std::unique_ptr<clipboard::ClipboardImpl> clipboard;
   std::unique_ptr<ws::AccessibilityManager> accessibility;
   std::unique_ptr<ws::WindowTreeHostFactory> window_tree_host_factory;
 };
@@ -296,10 +295,8 @@ void Service::Create(shell::Connection* connection,
 
 void Service::Create(shell::Connection* connection,
                      mojom::ClipboardRequest request) {
-  UserState* user_state = GetUserState(connection);
-  if (!user_state->clipboard)
-    user_state->clipboard.reset(new clipboard::ClipboardImpl);
-  user_state->clipboard->AddBinding(std::move(request));
+  const ws::UserId& user_id = connection->GetRemoteIdentity().user_id();
+  window_server_->GetClipboardForUser(user_id)->AddBinding(std::move(request));
 }
 
 void Service::Create(shell::Connection* connection,