Mandoline: Introduce ApplicationConnection::CloseConnection

mojo/application/public/cpp/application_delegate.h

Index: mojo/application/public/cpp/application_delegate.h
diff --git a/mojo/application/public/cpp/application_delegate.h b/mojo/application/public/cpp/application_delegate.h
index 2c3423fce58c12e681f0e22a81fe3aab40a2b58e..0d57097c048dbb51b1dce0f2628d9f71d7f30487 100644
--- a/mojo/application/public/cpp/application_delegate.h
+++ b/mojo/application/public/cpp/application_delegate.h
@@ -34,6 +34,10 @@ class ApplicationDelegate {
   // Return false to reject the connection entirely.
   virtual bool ConfigureOutgoingConnection(ApplicationConnection* connection);
 
+  // Called when an ApplicationConnection is about to close. After returning,
+  // the |connection| object will be destroyed.
+  virtual void OnWillCloseConnection(ApplicationConnection* connection) {}
+
   // Called before ApplicationImpl::Terminate(). After returning from this call
   // the delegate can no longer rely on the main run loop still running.
   virtual void Quit();