Let ActivityManager delete the remaining activities on shutdown.

athena/activity/activity.cc

Index: athena/activity/activity.cc
diff --git a/athena/activity/activity.cc b/athena/activity/activity.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6a33f02cb33be1877bb43b4e20875f909ae38c8c
--- /dev/null
+++ b/athena/activity/activity.cc
@@ -0,0 +1,15 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "athena/activity/public/activity.h"
+
+#include "athena/activity/public/activity_manager.h"
+
+namespace athena {
+
+Activity::~Activity() {
+  ActivityManager::Get()->RemoveActivity(this);
+}
+
+}  // namespace athena