Make metadata state local in the WebVTT parser

Source/core/html/track/WebVTTParser.cpp

 /*
  * 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 229 matching lines @@
     // 4.1 Extension of WebVTT header parsing (11 - 15)
     DEFINE_STATIC_LOCAL(const AtomicString, regionHeaderName, ("Region", AtomicString::ConstructFromLiteral));
 
     // 15.4 If line contains the character ":" (A U+003A COLON), then set metadata's
     // name to the substring of line before the first ":" character and
     // metadata's value to the substring after this character.
     if (!RuntimeEnabledFeatures::webVTTRegionsEnabled() || !line.contains(":"))
         return;
 
     unsigned colonPosition = line.find(":");
-    m_currentHeaderName = line.substring(0, colonPosition);
+    String headerName = line.substring(0, colonPosition);
 
     // 15.5 If metadata's name equals "Region":
-    if (m_currentHeaderName == regionHeaderName) {
-        m_currentHeaderValue = line.substring(colonPosition + 1, line.length() - 1);
+    if (headerName == regionHeaderName) {
+        String headerValue = line.substring(colonPosition + 1);
         // 15.5.1 - 15.5.8 Region creation: Let region be a new text track region [...]
-        createNewRegion();
+        createNewRegion(headerValue);
     }
 }
 
 WebVTTParser::ParseState WebVTTParser::collectCueId(const String& line)
 {
     if (line.contains("-->"))
         return collectTimingsAndSettings(line);
     m_currentId = line;
     return TimingsAndSettings;
 }
@@ skipping 119 matching lines @@
 
 void WebVTTParser::resetCueValues()
 {
     m_currentId = emptyString();
     m_currentSettings = emptyString();
     m_currentStartTime = 0;
     m_currentEndTime = 0;
     m_currentContent.clear();
 }
 
-void WebVTTParser::createNewRegion()
+void WebVTTParser::createNewRegion(const String& headerValue)
 {
-    if (!m_currentHeaderValue.length())
+    if (headerValue.isEmpty())
         return;
 
     RefPtr<VTTRegion> region = VTTRegion::create();
-    region->setRegionSettings(m_currentHeaderValue);
+    region->setRegionSettings(headerValue);
 
     // 15.5.10 If the text track list of regions regions contains a region
     // with the same region identifier value as region, remove that region.
     for (size_t i = 0; i < m_regionList.size(); ++i)
         if (m_regionList[i]->id() == region->id()) {
             m_regionList.remove(i);
             break;
         }
 
     m_regionList.append(region);
@@ skipping 148 matching lines @@
 }
 
 void WebVTTParser::skipWhiteSpace(const String& line, unsigned* position)
 {
     while (*position < line.length() && isASpace(line[*position]))
         (*position)++;
 }
 
 }