Move IN_OVERFLOW from Panel::ExpansionState to new enum.

chrome/browser/ui/panels/panel_browser_view.cc

Index: chrome/browser/ui/panels/panel_browser_view.cc
diff --git a/chrome/browser/ui/panels/panel_browser_view.cc b/chrome/browser/ui/panels/panel_browser_view.cc
index 6aa691255657c980d790b560b1649c54e27a02e4..422cb6cfb316b4dd276c635d4da072d404c32fe4 100644
--- a/chrome/browser/ui/panels/panel_browser_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_view.cc
@@ -496,10 +496,16 @@ bool PanelBrowserView::OnTitlebarMouseReleased() {
       base::TimeDelta::FromMilliseconds(kShortClickThresholdMs))
     return true;
 
-  Panel::ExpansionState new_expansion_state =
-    (panel_->expansion_state() != Panel::EXPANDED) ? Panel::EXPANDED
-                                                   : Panel::MINIMIZED;
-  panel_->SetExpansionState(new_expansion_state);
+  if (panel_->layout_state() == Panel::IN_OVERFLOW) {
+    panel_->SetExpansionState(Panel::EXPANDED);
+    panel_->SetLayoutState(Panel::DOCKED);
+  } else {
+    Panel::ExpansionState new_expansion_state =
+        (panel_->expansion_state() != Panel::EXPANDED) ? Panel::EXPANDED
+                                                       : Panel::MINIMIZED;
+    panel_->SetExpansionState(new_expansion_state);
+  }
+
   return true;
 }