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

chrome/browser/ui/panels/taskbar_window_thumbnailer_win.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_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
+#define CHROME_BROWSER_UI_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
+#pragma once
+
+#include "base/memory/scoped_ptr.h"
+#include "ui/base/win/hwnd_subclass.h"
+
+class SkBitmap;
+
+// Provides the custom thumbnail and live preview for the window that appears
+// in the taskbar (Windows 7 and later).
+class TaskbarWindowThumbnailerWin : public ui::HWNDMessageFilter {
+ public:
+  explicit TaskbarWindowThumbnailerWin(HWND hwnd);
+  virtual ~TaskbarWindowThumbnailerWin();
+
+  void Start();
+  void Stop();
+
+ private:
+  // Overridden from ui::HWNDMessageFilter:
+  virtual bool FilterMessage(HWND hwnd,
+                             UINT message,
+                             WPARAM w_param,
+                             LPARAM l_param,
+                             LRESULT* l_result) OVERRIDE;
+
+  // Message handlers.
+  bool OnDwmSendIconicThumbnail(
+      int width, int height, LRESULT* l_result);
+  bool OnDwmSendIconicLivePreviewBitmap(LRESULT* l_result);
+
+  // Captures and returns the screenshot of the window. The caller is
+  // responsible to release the returned SkBitmap instance.
+  SkBitmap* CaptureWindowImage() const;
+
+  HWND hwnd_;
+  scoped_ptr<SkBitmap> capture_bitmap_;
+
+  DISALLOW_COPY_AND_ASSIGN(TaskbarWindowThumbnailerWin);
+};
+
+#endif  // CHROME_BROWSER_UI_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_