[Panels] Fix browser crash when killing extension on Windows.

chrome/browser/ui/panels/panel_view.cc

Index: chrome/browser/ui/panels/panel_view.cc
diff --git a/chrome/browser/ui/panels/panel_view.cc b/chrome/browser/ui/panels/panel_view.cc
index d4f348daea194e660cc1fce6b6842cf900c59c33..3a761fe6a3caabfdd6ad2389a0f75c3a66eb307e 100644
--- a/chrome/browser/ui/panels/panel_view.cc
+++ b/chrome/browser/ui/panels/panel_view.cc
@@ -286,12 +286,26 @@ void PanelView::AnimationProgressed(const ui::Animation* animation) {
 }
 
 void PanelView::ClosePanel() {
+  // We're already closing. Do nothing.
+  if (!window_)
+    return;
+
+  if (!panel_->ShouldCloseWindow())
+    return;
+
   // Cancel any currently running animation since we're closing down.
   if (bounds_animator_.get())
     bounds_animator_.reset();
 
+  if (panel_->GetWebContents()) {

[jianli, 2012/09/19 01:09:43]

nit: could you please add comment for why we need to close web contents first?

[jennb, 2012/09/19 01:16:46]

Done. Stole wording from browser_view.cc

+    // When web contents are destroyed, we will be called back again.
+    panel_->OnWindowClosing();
+    return;
+  }
+
   panel_->OnNativePanelClosed();
   window_->Close();
+  window_ = NULL;
 }
 
 void PanelView::ActivatePanel() {