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

chrome/browser/ui/panels/overflow_panel_strip.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_UI_PANELS_OVERFLOW_PANEL_STRIP_H_
 #define CHROME_BROWSER_UI_PANELS_OVERFLOW_PANEL_STRIP_H_
 #pragma once
 
 #include <vector>
 #include "chrome/browser/ui/panels/panel.h"
@@ skipping 15 matching lines @@
  public:
   typedef std::vector<Panel*> Panels;
 
   explicit OverflowPanelStrip(PanelManager* panel_manager);
   virtual ~OverflowPanelStrip();
 
   // PanelStrip OVERRIDES:
   virtual void SetDisplayArea(const gfx::Rect& display_area) OVERRIDE;
   virtual void RefreshLayout() OVERRIDE;
   virtual void AddPanel(Panel* panel) OVERRIDE;
-  virtual bool RemovePanel(Panel* panel) OVERRIDE;
+  virtual void RemovePanel(Panel* panel) OVERRIDE;
   virtual void CloseAll() OVERRIDE;
   virtual void ResizePanelWindow(
       Panel* panel,
       const gfx::Size& preferred_window_size) OVERRIDE;
   virtual void OnPanelAttentionStateChanged(Panel* panel) OVERRIDE;
   virtual void ActivatePanel(Panel* panel) OVERRIDE;
   virtual void MinimizePanel(Panel* panel) OVERRIDE;
   virtual void RestorePanel(Panel* panel) OVERRIDE;
   virtual bool CanShowPanelAsActive(const Panel* panel) const OVERRIDE;
   virtual bool CanDragPanel(const Panel* panel) const OVERRIDE;
@@ skipping 94 matching lines @@
   int overflow_hover_animator_start_width_;
   int overflow_hover_animator_end_width_;
 
   // Invalid panel index.
   static const size_t kInvalidPanelIndex = static_cast<size_t>(-1);
 
   DISALLOW_COPY_AND_ASSIGN(OverflowPanelStrip);
 };
 
 #endif  // CHROME_BROWSER_UI_PANELS_OVERFLOW_PANEL_STRIP_H_