Use ScopedTaskEnvironment instead of MessageLoop in media/capture/ unit tests

media/capture/video/fake_video_capture_device_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 "media/capture/video/fake_video_capture_device.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/thread.h"
 #include "build/build_config.h"
 #include "media/base/media_switches.h"
 #include "media/capture/video/fake_video_capture_device_factory.h"
 #include "media/capture/video/video_capture_device.h"
 #include "media/capture/video_capture_types.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 165 matching lines @@
   virtual ~ImageCaptureClient() {}
 
   mojom::PhotoCapabilitiesPtr capabilities_;
 };
 
 }  // namespace
 
 class FakeVideoCaptureDeviceBase : public ::testing::Test {
  protected:
   FakeVideoCaptureDeviceBase()
-      : loop_(new base::MessageLoop()),
-        descriptors_(new VideoCaptureDeviceDescriptors()),
+      : descriptors_(new VideoCaptureDeviceDescriptors()),
         client_(CreateClient()),
         image_capture_client_(new ImageCaptureClient()),
         video_capture_device_factory_(new FakeVideoCaptureDeviceFactory()) {}
 
   void SetUp() override { EXPECT_CALL(*client_, OnError(_, _)).Times(0); }
 
   std::unique_ptr<MockClient> CreateClient() {
     return std::unique_ptr<MockClient>(new MockClient(base::Bind(
         &FakeVideoCaptureDeviceBase::OnFrameCaptured, base::Unretained(this))));
   }
 
   void OnFrameCaptured(const VideoCaptureFormat& format) {
     last_format_ = format;
     run_loop_->QuitClosure().Run();
   }
 
   void WaitForCapturedFrame() {
     run_loop_.reset(new base::RunLoop());
     run_loop_->Run();
   }
 
   const VideoCaptureFormat& last_format() const { return last_format_; }
 
-  const std::unique_ptr<base::MessageLoop> loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<VideoCaptureDeviceDescriptors> descriptors_;
   std::unique_ptr<base::RunLoop> run_loop_;
   std::unique_ptr<MockClient> client_;
   const scoped_refptr<ImageCaptureClient> image_capture_client_;
   VideoCaptureFormat last_format_;
   const std::unique_ptr<FakeVideoCaptureDeviceFactory>
       video_capture_device_factory_;
 };
 
 class FakeVideoCaptureDeviceTest
@@ skipping 372 matching lines @@
                                4u,
                                {PIXEL_FORMAT_I420, PIXEL_FORMAT_Y16,
                                 PIXEL_FORMAT_MJPEG, PIXEL_FORMAT_I420}},
            CommandLineTestData{"device-count=4,ownership=client",
                                20,
                                4u,
                                {PIXEL_FORMAT_I420, PIXEL_FORMAT_Y16,
                                 PIXEL_FORMAT_MJPEG, PIXEL_FORMAT_I420}},
            CommandLineTestData{"device-count=0", 20, 0u, {PIXEL_FORMAT_I420}}));
 };  // namespace media