Literal AtomicString construction can rely on strlen optimization.

third_party/WebKit/Source/core/html/track/vtt/VTTParser.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 197 matching lines @@
         return false;
     if (line.length() > fileIdentifierLength && !isASpace(line[fileIdentifierLength]))
         return false;
 
     return true;
 }
 
 void VTTParser::collectMetadataHeader(const String& line)
 {
     // WebVTT header parsing (WebVTT parser algorithm step 12)
-    DEFINE_STATIC_LOCAL(const AtomicString, regionHeaderName, ("Region", AtomicString::ConstructFromLiteral));
+    DEFINE_STATIC_LOCAL(const AtomicString, regionHeaderName, ("Region"));
 
     // The only currently supported header is the "Region" header.
     if (!RuntimeEnabledFeatures::webVTTRegionsEnabled())
         return;
 
     // Step 12.4 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.
     size_t colonPosition = line.find(':');
     if (colonPosition == kNotFound)
@@ skipping 330 matching lines @@
 }
 
 DEFINE_TRACE(VTTParser)
 {
     visitor->trace(m_document);
     visitor->trace(m_cueList);
     visitor->trace(m_regionList);
 }
 
 } // namespace blink