Don't treat Esc like Cancel in the external protocol dialog on Views.

chrome/browser/ui/views/external_protocol_dialog.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/views/external_protocol_dialog.h"
 
 #include <utility>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
@@ skipping 56 matching lines @@
 
 base::string16 ExternalProtocolDialog::GetWindowTitle() const {
   return delegate_->GetTitleText();
 }
 
 void ExternalProtocolDialog::DeleteDelegate() {
   delete this;
 }
 
 bool ExternalProtocolDialog::Cancel() {
-  // We also get called back here if the user closes the dialog or presses
-  // escape. In these cases it would be preferable to ignore the state of the
-  // check box but MessageBox doesn't distinguish this from pressing the cancel
-  // button.
   delegate_->DoCancel(delegate_->url(),
                       message_box_view_->IsCheckBoxSelected());
 
   ExternalProtocolHandler::RecordMetrics(
       message_box_view_->IsCheckBoxSelected());
 
   // Returning true closes the dialog.
   return true;
 }
 
 bool ExternalProtocolDialog::Accept() {
   // We record how long it takes the user to accept an external protocol.  If
   // users start accepting these dialogs too quickly, we should worry about
   // clickjacking.
   UMA_HISTOGRAM_LONG_TIMES("clickjacking.launch_url",
                            base::TimeTicks::Now() - creation_time_);
 
   ExternalProtocolHandler::RecordMetrics(
       message_box_view_->IsCheckBoxSelected());
 
   delegate_->DoAccept(delegate_->url(),
                       message_box_view_->IsCheckBoxSelected());
 
   // Returning true closes the dialog.
   return true;
 }
 
+bool ExternalProtocolDialog::Close() {

[msw, 2016/12/08 21:37:48]

Add a comment in the function body explaining why this override exists, and why
it shouldn't call the base class Close function. Add a unit test to ensure this
doesn't regress. 

+  delegate_->DoCancel(delegate_->url(), false);
+  return true;
+}
+
 views::View* ExternalProtocolDialog::GetContentsView() {
   return message_box_view_;
 }
 
 views::Widget* ExternalProtocolDialog::GetWidget() {
   return message_box_view_->GetWidget();
 }
 
 const views::Widget* ExternalProtocolDialog::GetWidget() const {
   return message_box_view_->GetWidget();
@@ skipping 19 matching lines @@
   message_box_view_ = new views::MessageBoxView(params);
   message_box_view_->SetCheckBoxLabel(delegate_->GetCheckboxText());
 
   WebContents* web_contents = tab_util::GetWebContentsByID(
       render_process_host_id_, routing_id_);
   // Only launch the dialog if there is a web contents associated with the
   // request.
   if (web_contents)
     constrained_window::ShowWebModalDialogViews(this, web_contents);
 }