Fix canPlayType() support for non-RFC compliant mp3 mimetype.

net/base/mime_util.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 <algorithm>
 #include <iterator>
 #include <map>
 #include <string>
 
 #include "base/containers/hash_tables.h"
@@ skipping 455 matching lines @@
 };
 
 static const MediaFormatStrict format_codec_mappings[] = {
   { "video/webm", "opus,vorbis,vp8,vp8.0,vp9,vp9.0" },
   { "audio/webm", "opus,vorbis" },
   { "audio/wav", "1" },
   { "audio/x-wav", "1" },
   { "video/ogg", "opus,theora,vorbis" },
   { "audio/ogg", "opus,vorbis" },
   { "application/ogg", "opus,theora,vorbis" },
-  { "audio/mpeg", "" },
+  { "audio/mpeg", ",mp3" }, // Note: The comma before the 'mp3'results in an
+                            // empty string codec ID and indicates
+                            // a missing codecs= parameter is also valid.
+                            // The presense of 'mp3' is not RFC compliant,
+                            // but is common in the wild so it is a defacto
+                            // standard.
   { "audio/mp3", "" },
   { "audio/x-mp3", "" }
 };
 
 // Following is the list of RFC 6381 compliant codecs:
 //   mp4a.6B     - MPEG-1 audio
 //   mp4a.69     - MPEG-2 extension to MPEG-1
 //   mp4a.67     - MPEG-2 AAC
 //   mp4a.40.2   - MPEG-4 AAC
 //   mp4a.40.5   - MPEG-4 HE-AAC
@@ skipping 25 matching lines @@
 MimeUtil::MimeUtil() {
   InitializeMimeTypeMaps();
 }
 
 // static
 bool MimeUtil::AreSupportedCodecs(const MimeMappings& supported_codecs,
                                   const std::vector<std::string>& codecs) {
   if (supported_codecs.empty())
     return codecs.empty();
 
+  // If no codecs are specified in the mimetype, check to see if a missing
+  // codecs parameter is allowed.
+  if (codecs.empty())
+    return supported_codecs.find(std::string()) != supported_codecs.end();
+
   for (size_t i = 0; i < codecs.size(); ++i) {
-    if (supported_codecs.find(codecs[i]) == supported_codecs.end())
+    if (codecs[i].empty() ||
+        supported_codecs.find(codecs[i]) == supported_codecs.end()) {
       return false;
+    }
   }
-  return !codecs.empty();
+
+  return true;
 }
 
 // Checks all the codecs present in the |codecs| against the entries in
 // |supported_codecs|. Returns true only if |codecs| is non-empty and all the
 // codecs match |supported_codecs| expressions.
 bool MimeUtil::AreSupportedCodecsWithProfile(
     const MimeExpressionMappings& supported_codecs,
     const std::vector<std::string>& codecs) {
   DCHECK(!supported_codecs.empty());
   for (size_t i = 0; i < codecs.size(); ++i) {
@@ skipping 638 matching lines @@
   post_data->append("\r\n" + value + "\r\n");
 }
 
 void AddMultipartFinalDelimiterForUpload(const std::string& mime_boundary,
                                          std::string* post_data) {
   DCHECK(post_data);
   post_data->append("--" + mime_boundary + "--\r\n");
 }
 
 }  // namespace net