Use ScopedTaskEnvironment instead of MessageLoopForUI in chromeos tests.

chromeos/audio/cras_audio_handler_unittest.cc

 // Copyright (c) 2013 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 "chromeos/audio/cras_audio_handler.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "chromeos/audio/audio_devices_pref_handler.h"
 #include "chromeos/audio/audio_devices_pref_handler_stub.h"
 #include "chromeos/dbus/audio_node.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/fake_cras_audio_client.h"
 #include "media/base/video_facing.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 217 matching lines @@
  private:
   base::ObserverList<media::VideoCaptureObserver> observers_;
   DISALLOW_COPY_AND_ASSIGN(FakeVideoCaptureManager);
 };
 
 }  // namespace
 
 // Test param is the version of stabel device id used by audio node.
 class CrasAudioHandlerTest : public testing::TestWithParam<int> {
  public:
-  CrasAudioHandlerTest() {}
+  CrasAudioHandlerTest()
+      : scoped_task_environment_(
+            base::test::ScopedTaskEnvironment::MainThreadType::UI) {}
   ~CrasAudioHandlerTest() override {}
 
   void SetUp() override {
     video_capture_manager_.reset(new FakeVideoCaptureManager);
   }
 
   void TearDown() override {
     cras_audio_handler_->RemoveAudioObserver(test_observer_.get());
     test_observer_.reset();
     video_capture_manager_->RemoveAllObservers();
@@ skipping 137 matching lines @@
     video_capture_manager_->NotifyVideoCaptureStarted(
         media::MEDIA_VIDEO_FACING_ENVIRONMENT);
   }
 
   void StopRearFacingCamera() {
     video_capture_manager_->NotifyVideoCaptureStopped(
         media::MEDIA_VIDEO_FACING_ENVIRONMENT);
   }
 
  protected:
-  base::MessageLoopForUI message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   CrasAudioHandler* cras_audio_handler_ = nullptr;         // Not owned.
   FakeCrasAudioClient* fake_cras_audio_client_ = nullptr;  // Not owned.
   std::unique_ptr<TestObserver> test_observer_;
   scoped_refptr<AudioDevicesPrefHandlerStub> audio_pref_handler_;
   std::unique_ptr<FakeVideoCaptureManager> video_capture_manager_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CrasAudioHandlerTest);
 };
 
@@ skipping 3553 matching lines @@
   // Verity the active mic does not change when there is still camera on.
   EXPECT_EQ(kRearMicId, cras_audio_handler_->GetPrimaryActiveInputNode());
 
   // Stop the rear mic.
   StopRearFacingCamera();
   // Verify the actice mic changes to front mic after both cameras stop.
   EXPECT_EQ(kFrontMicId, cras_audio_handler_->GetPrimaryActiveInputNode());
 }
 
 }  // namespace chromeos