Use ScopedTaskEnvironment instead of MessageLoopForUI in components tests.

components/component_updater/timer_unittest.cc

 // Copyright 2015 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 <string>
 
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/time/time.h"
 #include "components/component_updater/timer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using std::string;
 
 namespace component_updater {
 
 class ComponentUpdaterTimerTest : public testing::Test {
  public:
-  ComponentUpdaterTimerTest() {}
+  ComponentUpdaterTimerTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI) {}
   ~ComponentUpdaterTimerTest() override {}
 
  private:
-  base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 TEST_F(ComponentUpdaterTimerTest, Start) {
   class TimerClientFake {
    public:
     TimerClientFake(int max_count, const base::Closure& quit_closure)
         : max_count_(max_count), quit_closure_(quit_closure), count_(0) {}
 
     void OnTimerEvent() {
       ++count_;
@@ skipping 18 matching lines @@
   const base::TimeDelta delay(base::TimeDelta::FromMilliseconds(1));
   timer.Start(delay, delay, base::Bind(&TimerClientFake::OnTimerEvent,
                                        base::Unretained(&timer_client_fake)));
   run_loop.Run();
   timer.Stop();
 
   EXPECT_EQ(3, timer_client_fake.count());
 }
 
 }  // namespace component_updater