Use ScopedTaskEnvironment instead of MessageLoop in media unit tests.

media/base/media_url_demuxer_unittest.cc

 // Copyright 2016 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/base/media_url_demuxer.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace media {
 
 class MediaUrlDemuxerTest : public testing::Test {
  public:
   MediaUrlDemuxerTest()
       : default_media_url_("http://example.com/file.mp4"),
@@ skipping 10 matching lines @@
 
   void VerifyCallbackOk(PipelineStatus status) {
     EXPECT_EQ(PIPELINE_OK, status);
   }
 
   GURL default_media_url_;
   GURL default_first_party_url_;
   std::unique_ptr<Demuxer> demuxer_;
 
   // Necessary, or else base::ThreadTaskRunnerHandle::Get() fails.
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MediaUrlDemuxerTest);
 };
 
 TEST_F(MediaUrlDemuxerTest, BaseCase) {
   InitializeTest();
 
   EXPECT_EQ(MediaResource::Type::URL, demuxer_->GetType());
 
@@ skipping 23 matching lines @@
 TEST_F(MediaUrlDemuxerTest, SeekReturnsPipelineOk) {
   InitializeTest();
   demuxer_->Seek(base::TimeDelta(),
                  base::Bind(&MediaUrlDemuxerTest::VerifyCallbackOk,
                             base::Unretained(this)));
 
   base::RunLoop().RunUntilIdle();
 }
 
 }  // namespace media