Quit the message loop by default in ShellConnectionLost when ApplicationRunner is used

mojo/shell/public/cpp/shell_connection.h

Index: mojo/shell/public/cpp/shell_connection.h
diff --git a/mojo/shell/public/cpp/shell_connection.h b/mojo/shell/public/cpp/shell_connection.h
index a05f6f136676a5ba022a190215be3b117c22fdc7..3e00cd362c056cb2d1f69f123fb4a2294c43eb07 100644
--- a/mojo/shell/public/cpp/shell_connection.h
+++ b/mojo/shell/public/cpp/shell_connection.h
@@ -61,7 +61,12 @@ class ShellConnection : public shell::mojom::ShellClient {
   // TODO(rockot): Remove this once we get rid of app tests.
   void SetAppTestConnectorForTesting(shell::mojom::ConnectorPtr connector);
 
- private:
+  // Specify a function to be called when the connection to the shell is lost.
+  void set_connection_lost_closure(const base::Closure& closure) {
+    connection_lost_closure_ = closure;
+  }
+
+private:
   // shell::mojom::ShellClient:
   void Initialize(shell::mojom::IdentityPtr identity,
                   uint32_t id,
@@ -90,6 +95,8 @@ class ShellConnection : public shell::mojom::ShellClient {
   Binding<shell::mojom::ShellClient> binding_;
   scoped_ptr<Connector> connector_;
 
+  base::Closure connection_lost_closure_;
+
   DISALLOW_COPY_AND_ASSIGN(ShellConnection);
 };