Include <algorithm> if you use functions from <algorithm>.

content/renderer/media/media_stream.cc

 // Copyright 2014 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 "content/renderer/media/media_stream.h"
 
+#include <algorithm>
+
 #include "base/logging.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 
 namespace content {
 
 // static
 MediaStream* MediaStream::GetMediaStream(
     const blink::WebMediaStream& stream) {
   return static_cast<MediaStream*>(stream.extraData());
 }
@@ skipping 32 matching lines @@
 bool MediaStream::RemoveTrack(const blink::WebMediaStreamTrack& track) {
   DCHECK(thread_checker_.CalledOnValidThread());
   for (std::vector<MediaStreamObserver*>::iterator it = observers_.begin();
        it != observers_.end(); ++it) {
     (*it)->TrackRemoved(track);
   }
   return true;
 }
 
 }  // namespace content