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

chrome/browser/ui/views/external_protocol_dialog.cc

Index: chrome/browser/ui/views/external_protocol_dialog.cc
diff --git a/chrome/browser/ui/views/external_protocol_dialog.cc b/chrome/browser/ui/views/external_protocol_dialog.cc
index 60b15cfe11a6d74359538c3ba7d8d6f4818a6058..ef49430971cd7ef205332e0a155ed9da8e805c6d 100644
--- a/chrome/browser/ui/views/external_protocol_dialog.cc
+++ b/chrome/browser/ui/views/external_protocol_dialog.cc
@@ -74,10 +74,6 @@ void ExternalProtocolDialog::DeleteDelegate() {
 }
 
 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());
 
@@ -105,6 +101,11 @@ bool ExternalProtocolDialog::Accept() {
   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_;
 }