Use a direct include of strings headers in ipc/, jingle/, media/.

media/webm/webm_tracks_parser.cc

 // Copyright (c) 2012 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 "media/webm/webm_tracks_parser.h"
 
 #include "base/logging.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "media/base/buffers.h"
 #include "media/webm/webm_constants.h"
 #include "media/webm/webm_content_encodings.h"
 
 namespace media {
 
 static TextKind CodecIdToTextKind(const std::string& codec_id) {
   if (codec_id == kWebMCodecSubtitles)
     return kTextSubtitles;
 
@@ skipping 250 matching lines @@
 
   if (id == kWebMIdLanguage) {
     track_language_ = str;
     return true;
   }
 
   return true;
 }
 
 }  // namespace media