Use enum instead of string in MessageLoopFactory::GetMessageLoop*

media/filters/pipeline_integration_test_base.cc

Index: media/filters/pipeline_integration_test_base.cc
diff --git a/media/filters/pipeline_integration_test_base.cc b/media/filters/pipeline_integration_test_base.cc
index c5bdc2eaec2124b864a3ceb8e389f051df709167..cb560f01fa86b5d34900473668d41702f4d35cd8 100644
--- a/media/filters/pipeline_integration_test_base.cc
+++ b/media/filters/pipeline_integration_test_base.cc
@@ -191,11 +191,11 @@ PipelineIntegrationTestBase::CreateFilterCollection(
   collection->AddAudioDecoder(new FFmpegAudioDecoder(
       base::Bind(&MessageLoopFactory::GetMessageLoop,
                  base::Unretained(message_loop_factory_.get()),
-                 "AudioDecoderThread")));
+                 media::MessageLoopFactory::AUDIO_DECODER)));
   scoped_refptr<VideoDecoder> decoder = new FFmpegVideoDecoder(
       base::Bind(&MessageLoopFactory::GetMessageLoop,
                  base::Unretained(message_loop_factory_.get()),
-                 "VideoDecoderThread"),
+                 media::MessageLoopFactory::VIDEO_DECODER),
       decryptor);
   collection->AddVideoDecoder(decoder);
   // Disable frame dropping if hashing is enabled.