Use ScopedTaskEnvironment instead of MessageLoop in media unit tests.

media/gpu/android/media_codec_video_decoder_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/gpu/android/media_codec_video_decoder.h"
 #include "base/bind.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "media/base/android/media_codec_util.h"
 #include "media/base/test_helpers.h"
-#include "media/gpu/android/media_codec_video_decoder.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #define SKIP_IF_MEDIA_CODEC_IS_BLACKLISTED()                                 \
   do {                                                                       \
     if (!MediaCodecUtil::IsMediaCodecAvailable()) {                          \
       DVLOG(0) << "Skipping test: MediaCodec is blacklisted on this device"; \
       return;                                                                \
     }                                                                        \
   } while (0)
 
@@ skipping 15 matching lines @@
   bool Initialize(const VideoDecoderConfig& config) {
     bool result = false;
     mcvd_.Initialize(config, false, nullptr, base::Bind(&InitCb, &result),
                      base::Bind(&OutputCb));
     base::RunLoop().RunUntilIdle();
     return result;
   }
 
  private:
   MediaCodecVideoDecoder mcvd_;
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
 };
 
 TEST_F(MediaCodecVideoDecoderTest, DestructWithoutInit) {
   // Do nothing.
 }
 
 TEST_F(MediaCodecVideoDecoderTest, UnknownCodecIsRejected) {
   SKIP_IF_MEDIA_CODEC_IS_BLACKLISTED();
   ASSERT_FALSE(Initialize(TestVideoConfig::Invalid()));
 }
 
 TEST_F(MediaCodecVideoDecoderTest, H264IsSupported) {
   SKIP_IF_MEDIA_CODEC_IS_BLACKLISTED();
   // H264 is always supported by MCVD.
   ASSERT_TRUE(Initialize(TestVideoConfig::NormalH264()));
 }
 
 TEST_F(MediaCodecVideoDecoderTest, SmallVp8IsRejected) {
   SKIP_IF_MEDIA_CODEC_IS_BLACKLISTED();
   ASSERT_TRUE(Initialize(TestVideoConfig::NormalH264()));
 }
 
 }  // namespace media