Create video and audio decoder threads on demand.

media/filters/ffmpeg_video_decoder_unittest.cc

Index: media/filters/ffmpeg_video_decoder_unittest.cc
diff --git a/media/filters/ffmpeg_video_decoder_unittest.cc b/media/filters/ffmpeg_video_decoder_unittest.cc
index 7818a94592bc80bc3b1c172e868b83b9632b9862..580475ef65ef9ab3548e3dad14e7ff2df7d29523 100644
--- a/media/filters/ffmpeg_video_decoder_unittest.cc
+++ b/media/filters/ffmpeg_video_decoder_unittest.cc
@@ -18,6 +18,7 @@
 #include "media/base/test_data_util.h"
 #include "media/base/video_frame.h"
 #include "media/ffmpeg/ffmpeg_common.h"
+#include "media/filters/ffmpeg_decoder_unittest.h"
 #include "media/filters/ffmpeg_glue.h"
 #include "media/filters/ffmpeg_video_decoder.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -48,7 +49,8 @@ ACTION_P(ReturnBuffer, buffer) {
 class FFmpegVideoDecoderTest : public testing::Test {
  public:
   FFmpegVideoDecoderTest()
-      : decoder_(new FFmpegVideoDecoder(&message_loop_)),
+      : decoder_(new FFmpegVideoDecoder(base::Bind(&Identity<MessageLoop*>,
+                                                   &message_loop_))),
         demuxer_(new StrictMock<MockDemuxerStream>()),
         read_cb_(base::Bind(&FFmpegVideoDecoderTest::FrameReady,
                             base::Unretained(this))) {