Cleanup to keep panel from manipulating its panel strip assignment directly.

chrome/browser/ui/panels/detached_panel_strip.cc

Index: chrome/browser/ui/panels/detached_panel_strip.cc
diff --git a/chrome/browser/ui/panels/detached_panel_strip.cc b/chrome/browser/ui/panels/detached_panel_strip.cc
index c0e35acc42f22ff492f1563fbccca5d44eaee820..ced64fbf2ee38c56639e77316780868f43f203e4 100644
--- a/chrome/browser/ui/panels/detached_panel_strip.cc
+++ b/chrome/browser/ui/panels/detached_panel_strip.cc
@@ -34,12 +34,15 @@ void DetachedPanelStrip::RefreshLayout() {
 }
 
 void DetachedPanelStrip::AddPanel(Panel* panel) {
-  DCHECK_EQ(this, panel->panel_strip());
+  DCHECK_NE(this, panel->panel_strip());
+  panel->set_panel_strip(this);
   panels_.insert(panel);
 }
 
-bool DetachedPanelStrip::RemovePanel(Panel* panel) {
-  return panels_.erase(panel) != 0;
+void DetachedPanelStrip::RemovePanel(Panel* panel) {
+  DCHECK_EQ(this, panel->panel_strip());
+  panel->set_panel_strip(NULL);
+  panels_.erase(panel);
 }
 
 void DetachedPanelStrip::CloseAll() {
@@ -76,6 +79,12 @@ void DetachedPanelStrip::RestorePanel(Panel* panel) {
   NOTIMPLEMENTED();
 }
 
+bool DetachedPanelStrip::IsPanelMinimized(const Panel* panel) const {
+  DCHECK_EQ(this, panel->panel_strip());
+  NOTIMPLEMENTED();
+  return false;
+}
+
 bool DetachedPanelStrip::CanShowPanelAsActive(const Panel* panel) const {
   // All detached panels can be shown as active.
   return true;