Add overflow indicator count on Windows.

chrome/browser/ui/panels/panel_overflow_indicator.h

+// Copyright (c) 2011 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_PANEL_OVERFLOW_INDICATOR_H_
+#define CHROME_BROWSER_UI_PANELS_PANEL_OVERFLOW_INDICATOR_H_
+#pragma once
+
+#include "ui/gfx/rect.h"
+
+// An interfac that encapsulates the logic to support showing the overflow
+// indicator count "+N" for different platform.
+class PanelOverflowIndicator {
+ public:
+  static PanelOverflowIndicator* Create();
+
+  virtual ~PanelOverflowIndicator() { }
+
+  // Returns the height of indicator widget.
+  virtual int GetHeight() const = 0;
+
+  // Gets or sets the bounds, in screen coordinates.
+  virtual gfx::Rect GetBounds() const = 0;
+  virtual void SetBounds(const gfx::Rect& bounds) = 0;
+
+  // The count value reflects the number of additional overflow panels that are
+  // not shown.
+  virtual int GetCount() const = 0;
+  virtual void SetCount(int count) = 0;
+
+  // The indicator's background could be changed to draw the user's attention.
+  virtual void DrawAttention() = 0;
+  virtual void StopDrawingAttention() = 0;
+  virtual bool IsDrawingAttention() const = 0;
+};
+
+#endif  // CHROME_BROWSER_UI_PANELS_PANEL_OVERFLOW_INDICATOR_H_