Get the custom frame limping with win-aura.

ui/views/widget/widget_hwnd_utils.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_HWND_UTILS_H_
+#define UI_VIEWS_WIDGET_WIDGET_HWND_UTILS_H_
+#pragma once
+
+#include <windows.h>
+
+// Functions shared by native_widget_win.cc and widget_message_filter.cc:
+
+namespace views {
+
+// Returns true if the WINDOWPOS data provided indicates the client area of
+// the window may have changed size. This can be caused by the window being
+// resized or its frame changing.
+bool DidClientAreaSizeChange(const WINDOWPOS* window_pos);
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WIDGET_WIDGET_HWND_UTILS_H_