Webapp share dialog is not closed when client end of the connection is closed

remoting/host/it2me/it2me_confirmation_dialog_proxy.cc

Index: remoting/host/it2me/it2me_confirmation_dialog_proxy.cc
diff --git a/remoting/host/it2me/it2me_confirmation_dialog_proxy.cc b/remoting/host/it2me/it2me_confirmation_dialog_proxy.cc
index 82a542ca62c893e160b6c0a77dfc0b97976dfb91..d18b6b4dd85e3f53508dc9c2f05ff52800b7c454 100644
--- a/remoting/host/it2me/it2me_confirmation_dialog_proxy.cc
+++ b/remoting/host/it2me/it2me_confirmation_dialog_proxy.cc
@@ -102,10 +102,23 @@ void It2MeConfirmationDialogProxy::Show(
                             remote_user_email));
 }
 
+void It2MeConfirmationDialogProxy::Cancel() {
+  DCHECK(core_->caller_task_runner()->BelongsToCurrentThread());
+
+  if (callback_) {
+    core_->caller_task_runner()->PostTask(
+        FROM_HERE, base::Bind(base::ResetAndReturn(&callback_),
+                              It2MeConfirmationDialog::Result::CANCEL));
+  }
+}
+
 void It2MeConfirmationDialogProxy::ReportResult(
     It2MeConfirmationDialog::Result result) {
   DCHECK(core_->caller_task_runner()->BelongsToCurrentThread());
-  base::ResetAndReturn(&callback_).Run(result);
+
+  if (callback_) {
+    base::ResetAndReturn(&callback_).Run(result);
+  }
 }
 
 }  // namespace remoting