diff -r 000000000000 -r 6474c204b198 widget/windows/TaskbarTabPreview.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/windows/TaskbarTabPreview.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_TaskbarTabPreview_h__
+#define __mozilla_widget_TaskbarTabPreview_h__
+
+#include "nsITaskbarTabPreview.h"
+#include "TaskbarPreview.h"
+
+namespace mozilla {
+namespace widget {
+
+class TaskbarTabPreview : public nsITaskbarTabPreview,
+                          public TaskbarPreview
+{
+public:
+  TaskbarTabPreview(ITaskbarList4 *aTaskbar, nsITaskbarPreviewController *aController, HWND aHWND, nsIDocShell *aShell);
+  virtual ~TaskbarTabPreview();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARTABPREVIEW
+  NS_FORWARD_NSITASKBARPREVIEW(TaskbarPreview::)
+
+private:
+  virtual nsresult ShowActive(bool active);
+  virtual HWND &PreviewWindow();
+  virtual LRESULT WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam);
+  static LRESULT CALLBACK GlobalWndProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam);
+
+  virtual nsresult UpdateTaskbarProperties();
+  virtual nsresult Enable();
+  virtual nsresult Disable();
+  virtual void DetachFromNSWindow();
+
+  // WindowHook procedure for hooking mWnd
+  static bool MainWindowHook(void *aContext,
+                               HWND hWnd, UINT nMsg,
+                               WPARAM wParam, LPARAM lParam,
+                               LRESULT *aResult);
+
+  // Bug 520807 - we need to update the proxy window style based on the main
+  // window's style to workaround a bug with the way the DWM displays the
+  // previews.
+  void UpdateProxyWindowStyle();
+
+  nsresult UpdateTitle();
+  nsresult UpdateIcon();
+  nsresult UpdateNext();
+
+  // Handle to the toplevel proxy window
+  HWND                    mProxyWindow;
+  nsString                mTitle;
+  nsCOMPtr<imgIContainer> mIconImage;
+  // Cached Windows icon of mIconImage
+  HICON                   mIcon;
+  // Preview that follows this preview in the taskbar (left-to-right order)
+  nsCOMPtr<nsITaskbarTabPreview> mNext;
+  // True if this preview has been registered with the taskbar
+  bool                    mRegistered;
+};
+
+} // namespace widget
+} // namespace mozilla
+
+#endif /* __mozilla_widget_TaskbarTabPreview_h__ */