Cascade shutdown of instances

mash/quick_launch/quick_launch_application.cc

Index: mash/quick_launch/quick_launch_application.cc
diff --git a/mash/quick_launch/quick_launch_application.cc b/mash/quick_launch/quick_launch_application.cc
index c4887a4946d1155625859eec23e2ef4ba6763932..0f505a894d187d920a1813e93f533992fe7b133b 100644
--- a/mash/quick_launch/quick_launch_application.cc
+++ b/mash/quick_launch/quick_launch_application.cc
@@ -5,6 +5,7 @@
 #include "mash/quick_launch/quick_launch_application.h"
 
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "mojo/public/c/system/main.h"
@@ -105,5 +106,9 @@ bool QuickLaunchApplication::AcceptConnection(mojo::Connection* connection) {
   return true;
 }
 
+void QuickLaunchApplication::ShellConnectionLost() {
+  base::MessageLoop::current()->QuitWhenIdle();
+}
+
 }  // namespace quick_launch
 }  // namespace mash