Remove usage of ScopedTaskScheduler.

media/test/pipeline_integration_test_base.h

Index: media/test/pipeline_integration_test_base.h
diff --git a/media/test/pipeline_integration_test_base.h b/media/test/pipeline_integration_test_base.h
index 87f3c277770d899453fa42e6f588b42f1e2eea91..edda2110f24cab56de2d7cf0c3715cea23f068db 100644
--- a/media/test/pipeline_integration_test_base.h
+++ b/media/test/pipeline_integration_test_base.h
@@ -10,7 +10,8 @@
 
 #include "base/md5.h"
 #include "base/message_loop/message_loop.h"
-#include "base/test/scoped_task_scheduler.h"
+#include "base/test/scoped_task_environment.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "media/audio/clockless_audio_sink.h"
 #include "media/audio/null_audio_sink.h"
 #include "media/base/demuxer.h"
@@ -142,13 +143,14 @@ class PipelineIntegrationTestBase : public Pipeline::Client {
 
  protected:
   MediaLog media_log_;
-  base::MessageLoop message_loop_;
   base::MD5Context md5_context_;
   bool hashing_enabled_;
   bool clockless_playback_;
 
-  // TaskScheduler is used only for FFmpegDemuxer.
-  std::unique_ptr<base::test::ScopedTaskScheduler> task_scheduler_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
+  const scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_ =
+      base::ThreadTaskRunnerHandle::Get();
+
   std::unique_ptr<Demuxer> demuxer_;
   std::unique_ptr<DataSource> data_source_;
   std::unique_ptr<PipelineImpl> pipeline_;