Move IN_OVERFLOW from Panel::ExpansionState to new enum.

chrome/browser/ui/panels/panel_browser_frame_view.cc

Index: chrome/browser/ui/panels/panel_browser_frame_view.cc
diff --git a/chrome/browser/ui/panels/panel_browser_frame_view.cc b/chrome/browser/ui/panels/panel_browser_frame_view.cc
index fcec968184633f62c5ac189781a2e7fe87dd987f..05893f388bef1794c32f3a516b62c7e7c4a61800 100644
--- a/chrome/browser/ui/panels/panel_browser_frame_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_frame_view.cc
@@ -488,7 +488,7 @@ void PanelBrowserFrameView::Layout() {
   bool show_close_button = true;
   bool show_settings_button = true;
   bool show_title_label = true;
-  if (panel_browser_view_->panel()->expansion_state() == Panel::IN_OVERFLOW) {
+  if (panel_browser_view_->panel()->strip_owner() == Panel::IN_OVERFLOW) {
     if (width() <= IconOnlyWidth()) {
       show_close_button = false;
       show_settings_button = false;
@@ -846,7 +846,7 @@ void PanelBrowserFrameView::OnMouseEnterOrLeaveWindow(bool mouse_entered) {
 void PanelBrowserFrameView::UpdateSettingsButtonVisibility(
     bool focused, bool cursor_in_view) {
   // The settings button is not shown in the overflow state.
-  if (panel_browser_view_->panel()->expansion_state() == Panel::IN_OVERFLOW)
+  if (panel_browser_view_->panel()->strip_owner() == Panel::IN_OVERFLOW)
     return;
 
   bool is_settings_button_visible = focused || cursor_in_view;