Fixes for re-enabling more MSVC level 4 warnings: media/ edition

media/base/audio_video_metadata_extractor.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 "media/base/audio_video_metadata_extractor.h"
 
 #include "base/bind.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/time/time.h"
@@ skipping 218 matching lines @@
 AudioVideoMetadataExtractor::attached_images_bytes() const {
   DCHECK(extracted_);
   return attached_images_bytes_;
 }
 
 void AudioVideoMetadataExtractor::ExtractDictionary(
     AVDictionary* metadata, TagDictionary* raw_tags) {
   if (!metadata)
     return;
 
-  AVDictionaryEntry* tag = NULL;
-  while ((tag = av_dict_get(metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
+  for (AVDictionaryEntry* tag =
+           av_dict_get(metadata, "", NULL, AV_DICT_IGNORE_SUFFIX);
+       tag; tag = av_dict_get(metadata, "", tag, AV_DICT_IGNORE_SUFFIX)) {
     if (raw_tags->find(tag->key) == raw_tags->end())
       (*raw_tags)[tag->key] = tag->value;
 
     if (ExtractInt(tag, "rotate", &rotation_)) continue;
     if (ExtractString(tag, "album", &album_)) continue;
     if (ExtractString(tag, "artist", &artist_)) continue;
     if (ExtractString(tag, "comment", &comment_)) continue;
     if (ExtractString(tag, "copyright", &copyright_)) continue;
     if (ExtractString(tag, "date", &date_)) continue;
     if (ExtractInt(tag, "disc", &disc_)) continue;
     if (ExtractString(tag, "encoder", &encoder_)) continue;
     if (ExtractString(tag, "encoded_by", &encoded_by_)) continue;
     if (ExtractString(tag, "genre", &genre_)) continue;
     if (ExtractString(tag, "language", &language_)) continue;
     if (ExtractString(tag, "title", &title_)) continue;
     if (ExtractInt(tag, "track", &track_)) continue;
   }
 }
 
 }  // namespace media