Make "all user" services work when packaged.

mash/task_viewer/task_viewer.cc

Index: mash/task_viewer/task_viewer.cc
diff --git a/mash/task_viewer/task_viewer.cc b/mash/task_viewer/task_viewer.cc
index e3156c35696ba3b855a4ddd73e44daf5d28cb506..59b5469cd5d4f0bb5df8bca430408118026c2eec 100644
--- a/mash/task_viewer/task_viewer.cc
+++ b/mash/task_viewer/task_viewer.cc
@@ -186,6 +186,9 @@ class TaskViewerContents
       }
     }
   }
+  void OnServiceFailedToStart(
+      const service_manager::Identity& identity) override {
+  }
   void OnServiceStopped(const service_manager::Identity& identity) override {
     for (auto it = instances_.begin(); it != instances_.end(); ++it) {
       if ((*it)->identity == identity) {