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

remoting/host/it2me/it2me_confirmation_dialog_proxy.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/it2me/it2me_confirmation_dialog_proxy.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 84 matching lines @@
     const std::string& remote_user_email,
     const It2MeConfirmationDialog::ResultCallback& callback) {
   DCHECK(core_->caller_task_runner()->BelongsToCurrentThread());
 
   callback_ = callback;
   core_->ui_task_runner()->PostTask(
       FROM_HERE, base::Bind(&Core::Show, base::Unretained(core_.get()),
                             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