Rename misleading |is_ambiguous| parameter

media/base/mime_util_internal.cc

Index: media/base/mime_util_internal.cc
diff --git a/media/base/mime_util_internal.cc b/media/base/mime_util_internal.cc
index 02e2ab3ee0f05ce2b14f164cb6f1b72675f9b03c..ab828263ca85ae7ebcc40728b610b5f70b840b86 100644
--- a/media/base/mime_util_internal.cc
+++ b/media/base/mime_util_internal.cc
@@ -31,9 +31,9 @@ struct CodecIDMappings {
 // The "mp4a" strings come from RFC 6381.
 static const CodecIDMappings kUnambiguousCodecStringMap[] = {
     {"1", MimeUtil::PCM},  // We only allow this for WAV so it isn't ambiguous.
-    // avc1/avc3.XXXXXX may be unambiguous; handled by ParseAVCCodecId().
-    // hev1/hvc1.XXXXXX may be unambiguous; handled by ParseHEVCCodecID().
-    // vp9, vp9.0, vp09.xx.xx.xx.xx.xx.xx.xx may be unambiguous; handled by
+    // avc1/avc3.XXXXXX is handled by ParseAVCCodecId().
+    // hev1/hvc1.XXXXXX is handled by ParseHEVCCodecID().
+    // vp8, vp8.0, vp9, vp9.0, and vp09.xx.xx.xx.xx.xx.xx.xx are handled by

[kqyang, 2016/04/21 00:59:48]

vp8, vp8.0 are still handled in this map; only vp9, vp9.0 and vp09 are handled
in ParseVp9CodecID.

[ddorwin, 2016/04/21 02:09:50]

Done. Thanks.

     // ParseVp9CodecID().
     {"mp3", MimeUtil::MP3},
     // Following is the list of RFC 6381 compliant audio codec strings:
@@ -86,7 +86,6 @@ static const CodecIDMappings kAmbiguousCodecStringMap[] = {
     {"mp4a.40", MimeUtil::MPEG4_AAC},
     {"avc1", MimeUtil::H264},
     {"avc3", MimeUtil::H264},
-    // avc1/avc3.XXXXXX may be ambiguous; handled by ParseAVCCodecId().
 };
 
 #if BUILDFLAG(ENABLE_MSE_MPEG2TS_STREAM_PARSER)
@@ -158,26 +157,14 @@ static bool IsValidH264Level(uint8_t level_idc) {
 // crbug.com/482761
 static bool ParseHEVCCodecID(const std::string& codec_id,
                              MimeUtil::Codec* codec,
-                             bool* is_ambiguous) {
+                             bool* is_known_supported) {
   if (base::StartsWith(codec_id, "hev1.", base::CompareCase::SENSITIVE) ||
       base::StartsWith(codec_id, "hvc1.", base::CompareCase::SENSITIVE)) {
     *codec = MimeUtil::HEVC_MAIN;
 
     // TODO(servolk): Full HEVC codec id parsing is not implemented yet (see
-    // crbug.com/482761). So treat HEVC codec ids as ambiguous for now.
-    *is_ambiguous = true;
-
-    // TODO(servolk): Most HEVC codec ids are treated as ambiguous (see above),
-    // but we need to recognize at least one valid unambiguous HEVC codec id,
-    // which is added into kMP4VideoCodecsExpression. We need it to be
-    // unambiguous to avoid DCHECK(!is_ambiguous) in InitializeMimeTypeMaps. We
-    // also use these in unit tests (see
-    // content/browser/media/media_canplaytype_browsertest.cc).
-    // Remove this workaround after crbug.com/482761 is fixed.
-    if (codec_id == "hev1.1.6.L93.B0" || codec_id == "hvc1.1.6.L93.B0") {
-      *is_ambiguous = false;
-    }
-
+    // crbug.com/482761). So treat HEVC as not known supported for now.
+    *is_known_supported = false;
     return true;
   }
 
@@ -306,10 +293,10 @@ SupportsType MimeUtil::AreSupportedCodecs(
 
   SupportsType result = IsSupported;
   for (size_t i = 0; i < codecs.size(); ++i) {
-    bool is_ambiguous = true;
+    bool is_known_supported = false;
     Codec codec = INVALID_CODEC;
-    if (!StringToCodec(mime_type_lower_case, codecs[i], &codec, &is_ambiguous,
-                       is_encrypted)) {
+    if (!StringToCodec(mime_type_lower_case, codecs[i], &codec,
+                       &is_known_supported, is_encrypted)) {
       return IsNotSupported;
     }
 
@@ -318,7 +305,7 @@ SupportsType MimeUtil::AreSupportedCodecs(
       return IsNotSupported;
     }
 
-    if (is_ambiguous)
+    if (!is_known_supported)
       result = MayBeSupported;
   }
 
@@ -669,13 +656,13 @@ bool MimeUtil::IsCodecSupportedOnPlatform(
 bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,
                              const std::string& codec_id,
                              Codec* codec,
-                             bool* is_ambiguous,
+                             bool* is_known_supported,
                              bool is_encrypted) const {
   StringToCodecMappings::const_iterator itr =
       string_to_codec_map_.find(codec_id);
   if (itr != string_to_codec_map_.end()) {
     *codec = itr->second.codec;
-    *is_ambiguous = itr->second.is_ambiguous;
+    *is_known_supported = !itr->second.is_ambiguous;
     return true;
   }
 
@@ -684,7 +671,7 @@ bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,
 // ones that are not added to the |string_to_codec_map_| and require parsing.
 
 #if BUILDFLAG(ENABLE_HEVC_DEMUXING)
-  if (ParseHEVCCodecID(codec_id, codec, is_ambiguous)) {
+  if (ParseHEVCCodecID(codec_id, codec, is_known_supported)) {
     return true;
   }
 #endif
@@ -701,7 +688,7 @@ bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,
         if (is_encrypted) {
           // FFmpeg is not generally used for encrypted videos, so we do not
           // know whether 10-bit is supported.
-          *is_ambiguous = true;
+          *is_known_supported = false;
           break;
         }
 // Fall through.
@@ -710,10 +697,10 @@ bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,
       case H264PROFILE_BASELINE:
       case H264PROFILE_MAIN:
       case H264PROFILE_HIGH:
-        *is_ambiguous = !IsValidH264Level(level_idc);
+        *is_known_supported = IsValidH264Level(level_idc);
         break;
       default:
-        *is_ambiguous = true;
+        *is_known_supported = false;
     }
     return true;
   }
@@ -723,13 +710,13 @@ bool MimeUtil::StringToCodec(const std::string& mime_type_lower_case,
     switch (profile) {
       case VP9PROFILE_PROFILE0:
         // Profile 0 should always be supported if VP9 is supported.
-        *is_ambiguous = false;
+        *is_known_supported = true;
         break;
       default:
         // We don't know if the underlying platform supports these profiles.
         // Need to add platform level querying to get supported profiles
         // (crbug/604566).
-        *is_ambiguous = true;
+        *is_known_supported = false;
     }
     return true;
   }