Add missing IWYU message_loop.h includes.

media/filters/vpx_video_decoder_fuzzertest.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 <stddef.h>
 #include <stdint.h>
 
 #include <random>
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/media.h"
 #include "media/base/media_util.h"
 #include "media/filters/vpx_video_decoder.h"
 
 using namespace media;
 
 struct Env {
   Env() {
@@ skipping 86 matching lines @@
   {
     base::RunLoop run_loop;
     auto buffer = DecoderBuffer::CopyFrom(data, size);
     decoder.Decode(buffer,
                    base::Bind(&OnDecodeComplete, run_loop.QuitClosure()));
     run_loop.Run();
   }
 
   return 0;
 }