Ensure default dialog button focus remains after a dialog update.

ui/views/window/dialog_client_view.cc

Index: ui/views/window/dialog_client_view.cc
diff --git a/ui/views/window/dialog_client_view.cc b/ui/views/window/dialog_client_view.cc
index 5d543a7572efe2b85b8772f293c766cbdb19430f..e8c3838015e85c9ef1d79c1ce38ad4998a422b92 100644
--- a/ui/views/window/dialog_client_view.cc
+++ b/ui/views/window/dialog_client_view.cc
@@ -319,6 +319,7 @@ void DialogClientView::SetupLayout() {
   base::AutoReset<bool> auto_reset(&adding_or_removing_views_, true);
   GridLayout* layout = new GridLayout(button_row_container_);
   layout->set_minimum_size(minimum_size_);
+  default_focus_ = GetDialogDelegate()->GetInitiallyFocusedView();

[sky, 2017/04/28 20:49:52]

There should be no need for the member as it's only used in this function. I
think you need to do the following:

You'll need null checks here!

View* focused_view = GetFocusManager()->GetFocusedView();
Then add an observer on focused_view.

reset of function

at end:
// You'll need null check here too!
if (!GetFocusManager()->GetFocusedView() && focused_view)
  focused_view->RequestFocus();

The observer tracks OnViewIsDeleting and sets focused_view to null. This is
necessary as SetupLayout has side effects that could do weird things.

[ackermanb, 2017/05/17 17:20:54]

Done.

 
   // Clobber any existing LayoutManager since it has weak references to child
   // Views which may be removed by SetupViews().
@@ -399,6 +400,12 @@ void DialogClientView::SetupLayout() {
       column_set->LinkColumnSizes(link[0], link[1], link[2], -1);
   }
   layout->AddPaddingRow(kFixed, insets.bottom());
+
+  // The default focus is lost when child views are added back into the dialog.
+  // This restores focus to the default.
+  if (default_focus_) {
+    default_focus_->RequestFocus();
+  }
 }
 
 void DialogClientView::SetupViews() {