aura: Fix views_unittests on linux.

views/controls/scrollbar/native_scroll_bar_wayland.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/controls/scrollbar/native_scroll_bar.h"
-#include "views/controls/scrollbar/native_scroll_bar_views.h"
-#include "views/controls/scrollbar/native_scroll_bar_wrapper.h"
-
-namespace views {
-
-////////////////////////////////////////////////////////////////////////////////
-// NativewScrollBarWrapper, public:
-
-// static
-NativeScrollBarWrapper* NativeScrollBarWrapper::CreateWrapper(
-    NativeScrollBar* scroll_bar) {
-  return new NativeScrollBarViews(scroll_bar);
-}
-
-// static
-int NativeScrollBarWrapper::GetHorizontalScrollBarHeight() {
-  return 20;
-}
-
-// static
-int NativeScrollBarWrapper::GetVerticalScrollBarWidth() {
-  return 20;
-}
-
-}  // namespace views