Support painting panel in iconified mode on Windows.

chrome/browser/ui/panels/panel.h

Index: chrome/browser/ui/panels/panel.h
diff --git a/chrome/browser/ui/panels/panel.h b/chrome/browser/ui/panels/panel.h
index e7a8ffdcbea408aaf106221828c38da099a363b7..c283a59d1e29c8fc68dc974f410021058ef7e3b7 100644
--- a/chrome/browser/ui/panels/panel.h
+++ b/chrome/browser/ui/panels/panel.h
@@ -39,7 +39,10 @@ class Panel : public BrowserWindow,
    // The panel is shown with the title-bar only.
    TITLE_ONLY,
    // The panel is shown with 3-pixel line.
-   MINIMIZED
+   MINIMIZED,
+   // The panel is put into the overflow area due to no space available in the
+   // normal display area.
+   IN_OVERFLOW
   };
 
   // The panel can be minimized to 4-pixel lines.