Revert of media::FFmpegVideoDecoder: remove ctor param |task_runner| and use a ThreadChecker instead.

content/common/gpu/media/video_encode_accelerator_unittest.cc

 // Copyright 2013 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 <inttypes.h>
 
 #include <algorithm>
 #include <queue>
 #include <string>
 
@@ skipping 621 matching lines @@
   State decoder_state_;
   std::queue<scoped_refptr<media::VideoFrame>> original_frames_;
   std::queue<scoped_refptr<media::DecoderBuffer>> decode_buffers_;
 };
 
 VideoFrameQualityValidator::VideoFrameQualityValidator(
     const media::VideoCodecProfile profile,
     const base::Closure& flush_complete_cb,
     const base::Closure& decode_error_cb)
     : profile_(profile),
-      decoder_(new media::FFmpegVideoDecoder()),
+      decoder_(new media::FFmpegVideoDecoder(base::MessageLoop::current()
+                                                 ->task_runner())),
       decode_cb_(base::Bind(&VideoFrameQualityValidator::DecodeDone,
                             base::Unretained(this))),
       eos_decode_cb_(base::Bind(&VideoFrameQualityValidator::FlushDone,
                                 base::Unretained(this))),
       flush_complete_cb_(flush_complete_cb),
       decode_error_cb_(decode_error_cb),
       decoder_state_(UNINITIALIZED) {
   // Allow decoding of individual NALU. Entire frames are required by default.
   decoder_->set_decode_nalus(true);
 }
@@ skipping 1115 matching lines @@
 
   content::g_env =
       reinterpret_cast<content::VideoEncodeAcceleratorTestEnvironment*>(
           testing::AddGlobalTestEnvironment(
               new content::VideoEncodeAcceleratorTestEnvironment(
                   test_stream_data.Pass(), log_path, run_at_fps,
                   needs_encode_latency, verify_all_output)));
 
   return RUN_ALL_TESTS();
 }