Use ScopedTaskEnvironment instead of MessageLoopForUI in ui tests.

ui/gfx/animation/slide_animation_unittest.cc

 // 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.
 
 #include "ui/gfx/animation/slide_animation.h"
 
 #include <memory>
 
 #include "base/macros.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/animation/test_animation_delegate.h"
 
 namespace gfx {
 
 // Class to provide access to SlideAnimation internals for testing.
 class SlideAnimation::TestApi {
  public:
   explicit TestApi(SlideAnimation* animation) : animation_(animation) {}
 
   void SetStartTime(base::TimeTicks ticks) {
     animation_->SetStartTime(ticks);
   }
 
   void Step(base::TimeTicks ticks) {
     animation_->Step(ticks);
   }
 
  private:
   SlideAnimation* animation_;
 
   DISALLOW_COPY_AND_ASSIGN(TestApi);
 };
 
 ////////////////////////////////////////////////////////////////////////////////
 // SlideAnimationTest
 class SlideAnimationTest: public testing::Test {
+ protected:
+  SlideAnimationTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI) {}
+
  private:
-  base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 // Tests animation construction.
 TEST_F(SlideAnimationTest, InitialState) {
   SlideAnimation animation(nullptr);
   // By default, slide animations are 60 Hz, so the timer interval should be
   // 1/60th of a second.
   EXPECT_EQ(1000 / 60, animation.timer_interval().InMilliseconds());
   // Duration defaults to 120 ms.
   EXPECT_EQ(120, animation.GetSlideDuration());
@@ skipping 48 matching lines @@
 
   // Delete the animation.
   animation.reset();
 
   // Make sure the delegate wasn't notified.
   EXPECT_FALSE(delegate.finished());
   EXPECT_FALSE(delegate.canceled());
 }
 
 }  // namespace gfx