Support auto-hide taskbar for panels on Windows.

views/widget/monitor_win.h

Index: views/widget/monitor_win.h
===================================================================
--- views/widget/monitor_win.h	(revision 98834)
+++ views/widget/monitor_win.h	(working copy)
@@ -6,6 +6,7 @@
 #define VIEWS_WIDGET_MONITOR_WIN_H_
 #pragma once
 
+#include <windows.h>
 #include "views/views_export.h"
 
 namespace gfx {
@@ -18,6 +19,11 @@
 // intersection with the specified rectangle.
 VIEWS_EXPORT gfx::Rect GetMonitorBoundsForRect(const gfx::Rect& rect);
 
+// Returns the always-on-top auto-hiding taskbar for edge |edge| (one of
+// ABE_LEFT, TOP, RIGHT, or BOTTOM) of monitor |monitor|. NULL is returned
+// if nothing is found.
+VIEWS_EXPORT HWND GetTopmostAutoHideTaskbarForEdge(UINT edge, HMONITOR monitor);
+
 }  // namespace views
 
 #endif  // VIEWS_WIDGET_MONITOR_WIN_H_