Support auto-hide taskbar for panels on Windows.

views/widget/monitor_win.cc

 // 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.
 
 #include "views/widget/monitor_win.h"
 
-#include <windows.h>
+#include <shellapi.h>
 
 #include "base/logging.h"
 #include "ui/gfx/rect.h"
 
 namespace views {
 
 gfx::Rect GetMonitorBoundsForRect(const gfx::Rect& rect) {
   RECT p_rect = rect.ToRECT();
   HMONITOR monitor = MonitorFromRect(&p_rect, MONITOR_DEFAULTTONEAREST);
   if (monitor) {
     MONITORINFO mi = {0};
     mi.cbSize = sizeof(mi);
     GetMonitorInfo(monitor, &mi);
     return gfx::Rect(mi.rcWork);
   }
   NOTREACHED();
   return gfx::Rect();
 }
 
+HWND GetTopmostAutoHideTaskbarForEdge(UINT edge, HMONITOR monitor) {
+  APPBARDATA taskbar_data =  { sizeof APPBARDATA, NULL, 0, edge };
+  HWND taskbar = reinterpret_cast<HWND>(SHAppBarMessage(ABM_GETAUTOHIDEBAR,
+                                                        &taskbar_data));
+  return (::IsWindow(taskbar) && (monitor != NULL) &&
+         (MonitorFromWindow(taskbar, MONITOR_DEFAULTTONULL) == monitor) &&
+         (GetWindowLong(taskbar, GWL_EXSTYLE) & WS_EX_TOPMOST)) ?
+      taskbar : NULL;
+}
+
 }  // namespace views