views: add focus ring to TreeView

ui/views/controls/scroll_view.cc

Index: ui/views/controls/scroll_view.cc
diff --git a/ui/views/controls/scroll_view.cc b/ui/views/controls/scroll_view.cc
index 68ee68fee3eaa8561e097be266a8ec202f448155..cd09df95662eae55a5bf8fdaf1bb266ce13cac7c 100644
--- a/ui/views/controls/scroll_view.cc
+++ b/ui/views/controls/scroll_view.cc
@@ -12,6 +12,7 @@
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/background.h"
 #include "ui/views/border.h"
+#include "ui/views/controls/focus_ring.h"
 #include "ui/views/style/platform_style.h"
 #include "ui/views/widget/widget.h"
 
@@ -294,6 +295,11 @@ int ScrollView::GetHeightForWidth(int width) const {
 }
 
 void ScrollView::Layout() {
+  // If there's a focus ring, lay it out first.
+  for (int i = 0; i < child_count(); ++i)

[sky, 2016/10/12 20:08:53]

I suspect tree isn't the only place that wants scrollview to have a focusring.
How about adding explicit functions to ScrollView for install/uninstall the
focusring and then Scrollview can cache the focus_ring_ and call Layout on it?
That matches what we do in Textfield.

[Elly Fong-Jones, 2016/10/12 21:10:22]

Done.

+    if (child_at(i)->GetClassName() == FocusRing::kViewClassName)
+      child_at(i)->Layout();
+
   gfx::Rect available_rect = GetContentsBounds();
   if (is_bounded()) {
     int content_width = available_rect.width();