mojo: shell::Context should outlive the shell MessageLoop

mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc

Index: mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc
diff --git a/mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc b/mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc
index 86b7f685e5215f8c6316d86be9da513c5074a896..8930a7aabcdcf084b9728f29ddd3f7d831da2038 100644
--- a/mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc
+++ b/mojo/services/public/cpp/view_manager/tests/view_manager_unittest.cc
@@ -392,7 +392,6 @@ class ViewManagerTest : public testing::Test {
 
   base::RunLoop* connect_loop_;
   shell::ShellTestHelper test_helper_;
-  base::MessageLoop loop_;
   ViewManagerInitServicePtr view_manager_init_;
   // Used to receive the most recent view manager loaded by an embed action.
   ViewManager* loaded_view_manager_;