Drop all uses of //base except ObserverList from view mgr client lib

services/window_manager/window_manager_app.cc

Index: services/window_manager/window_manager_app.cc
diff --git a/services/window_manager/window_manager_app.cc b/services/window_manager/window_manager_app.cc
index 18d68e33e51ba86c46acc41df4135c34ebe25cec..c35c5ff963b2fce9ad5980b73e40f4f15750f0be 100644
--- a/services/window_manager/window_manager_app.cc
+++ b/services/window_manager/window_manager_app.cc
@@ -371,11 +371,11 @@ void WindowManagerApp::CreateWindowManagerForViewManagerClient(
 
 void WindowManagerApp::SetViewManagerClient(
     mojo::ScopedMessagePipeHandle view_manager_client_request) {
-  view_manager_client_ =
+  view_manager_client_.reset(
       mojo::ViewManagerClientFactory::WeakBindViewManagerToPipe(
           mojo::MakeRequest<mojo::ViewManagerClient>(
               view_manager_client_request.Pass()),
-          view_manager_service_.Pass(), shell_, this).Pass();
+          view_manager_service_.Pass(), shell_, this));
 }
 
 }  // namespace window_manager