Don't allow form-feed (U+000C) as a WebVTT signature separator

third_party/WebKit/Source/core/html/track/vtt/VTTParser.h

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 40 matching lines @@
 public:
     virtual ~VTTParserClient() { }
 
     virtual void newCuesParsed() = 0;
     virtual void newRegionsParsed() = 0;
     virtual void fileFailedToParse() = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 };
 
+// Implementation of the WebVTT parser algorithm.
+// https://w3c.github.io/webvtt/#webvtt-parser-algorithm
 class VTTParser final : public GarbageCollectedFinalized<VTTParser> {
 public:
     enum ParseState {
         Initial,
         Header,
         Id,
         TimingsAndSettings,
         CueText,
         BadCue
     };
 
     static VTTParser* create(VTTParserClient* client, Document& document)
     {
         return new VTTParser(client, document);
     }
     ~VTTParser()
     {
     }
 
     static inline bool isRecognizedTag(const AtomicString& tagName)
     {
         return tagName == HTMLNames::iTag
             || tagName == HTMLNames::bTag
             || tagName == HTMLNames::uTag
             || tagName == HTMLNames::rubyTag
             || tagName == HTMLNames::rtTag;
     }
     static inline bool isASpace(UChar c)
     {
-        // WebVTT space characters are U+0020 SPACE, U+0009 CHARACTER TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), and U+000D CARRIAGE RETURN    (CR).
+        // WebVTT space characters are U+0020 SPACE, U+0009 CHARACTER
+        // TABULATION (tab), U+000A LINE FEED (LF), U+000C FORM FEED (FF), and
+        // U+000D CARRIAGE RETURN (CR).
         return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r';
     }
     static inline bool isValidSettingDelimiter(UChar c)
     {
         // ... a WebVTT cue consists of zero or more of the following components, in any order, separated from each other by one or more
         // U+0020 SPACE characters or U+0009 CHARACTER TABULATION (tab) characters.
         return c == ' ' || c == '\t';
     }
     static bool collectTimeStamp(const String&, double& timeStamp);
 
@@ skipping 48 matching lines @@
     Member<VTTParserClient> m_client;
 
     HeapVector<Member<TextTrackCue>> m_cueList;
 
     HeapVector<Member<VTTRegion>> m_regionList;
 };
 
 } // namespace blink
 
 #endif