Use ScopedTaskEnvironment instead of MessageLoopForUI in ui tests.

ui/events/gestures/gesture_provider_aura_unittest.cc

 // Copyright 2014 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/events/gestures/gesture_provider_aura.h"
 
 #include <memory>
 
-#include "base/message_loop/message_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/event_utils.h"
 
 namespace ui {
 
 class GestureProviderAuraTest : public testing::Test,
                                 public GestureProviderAuraClient {
  public:
-  GestureProviderAuraTest() {}
+  GestureProviderAuraTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI) {}
 
   ~GestureProviderAuraTest() override {}
 
   void OnGestureEvent(GestureConsumer* raw_input_consumer,
                       GestureEvent* event) override {}
 
   void SetUp() override {
     consumer_.reset(new GestureConsumer());
     provider_.reset(new GestureProviderAura(consumer_.get(), this));
   }
 
   void TearDown() override { provider_.reset(); }
 
   GestureProviderAura* provider() { return provider_.get(); }
 
  private:
   std::unique_ptr<GestureConsumer> consumer_;
   std::unique_ptr<GestureProviderAura> provider_;
-  base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 TEST_F(GestureProviderAuraTest, IgnoresExtraPressEvents) {
   base::TimeTicks time = ui::EventTimeForNow();
   TouchEvent press1(
       ET_TOUCH_PRESSED, gfx::Point(10, 10), time,
       PointerDetails(ui::EventPointerType::POINTER_TYPE_TOUCH, 0));
   EXPECT_TRUE(provider()->OnTouchEvent(&press1));
 
   time += base::TimeDelta::FromMilliseconds(10);
@@ skipping 85 matching lines @@
   pointerDetails2.radius_y += 1;
   TouchEvent move0_4(ET_TOUCH_MOVED, gfx::Point(), time, pointerDetails2, 0,
                      kAngle);
   move0_4.set_location_f(gfx::PointF(70, 75.1f));
   move0_4.set_root_location_f(gfx::PointF(70, 75.1f));
 }
 
 // TODO(jdduke): Test whether event marked as scroll trigger.
 
 }  // namespace ui