Remove last MD reference from TrayPopupUtils.

ui/views/test/test_slider.cc

Index: ui/views/test/test_slider.cc
diff --git a/ui/views/test/test_slider.cc b/ui/views/test/test_slider.cc
deleted file mode 100644
index 72d70985fe2c1333872a5a1a16cbcc0d849bdd83..0000000000000000000000000000000000000000
--- a/ui/views/test/test_slider.cc
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright 2016 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 "ui/views/test/test_slider.h"
-
-#include "ui/views/controls/slider.h"
-
-namespace views {
-
-// Arbitrary thumb size used for tests.
-const int thumb_size_ = 10;
-
-TestSlider::TestSlider(SliderListener* listener) : Slider(listener) {}
-
-TestSlider::~TestSlider() {}
-
-void TestSlider::UpdateState(bool control_on) {
-}
-
-const char* TestSlider::GetClassName() const {
-  return "TestSlider";
-}
-
-int TestSlider::GetThumbWidth() {
-  return thumb_size_;
-}
-
-}  // namespace views