Fix bug 105043: Panels [WIN]: For minimize panels, taskbar hover preview show the 4-pixel represent…

ui/views/widget/widget_delegate.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 UI_VIEWS_WIDGET_WIDGET_DELEGATE_H_
 #define UI_VIEWS_WIDGET_WIDGET_DELEGATE_H_
 #pragma once
 
 #include <string>
 
@@ skipping 129 matching lines @@
   // Called by the Widget to create the NonClient Frame View for this widget.
   // Return NULL to use the default one.
   virtual NonClientFrameView* CreateNonClientFrameView(Widget* widget);
 
   // Returns true if the window can be notified with the work area change.
   // Otherwise, the work area change for the top window will be processed by
   // the default window manager. In some cases, like panel, we would like to
   // manage the positions by ourselves.
   virtual bool WillProcessWorkAreaChange() const;
 
+  // Returns the preview image that appears when a user moves the mouse
+  // pointer over the window's thumbnail in the taskbar. This is only supported
+  // int Windows 7 and later.
+  // The returned image should not exceed |size|. If |live| is true, the image
+  // is used for live preview. Otherwise, it is shown as thumbnail.
+  virtual SkBitmap GetPreviewImage(const gfx::Size& size, bool live);
+
  protected:
   virtual ~WidgetDelegate() {}
 
  private:
   View* default_contents_view_;
 
   DISALLOW_COPY_AND_ASSIGN(WidgetDelegate);
 };
 
 // A WidgetDelegate implementation that is-a View. Used to override GetWidget()
 // to call View's GetWidget() for the common case where a WidgetDelegate
 // implementation is-a View.
 class VIEWS_EXPORT WidgetDelegateView : public WidgetDelegate, public View {
  public:
   WidgetDelegateView();
   virtual ~WidgetDelegateView();
 
   // Overridden from WidgetDelegate:
   virtual Widget* GetWidget() OVERRIDE;
   virtual const Widget* GetWidget() const OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(WidgetDelegateView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_DELEGATE_H_