Add metrics for style update time before FCP.

third_party/WebKit/Source/web/WebPerformance.cpp

 /*
  * Copyright (C) 2010 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 184 matching lines @@
   return millisecondsToSeconds(
       m_private->timing()
           ->parseBlockedOnScriptExecutionFromDocumentWriteDuration());
 }
 
 double WebPerformance::authorStyleSheetParseDurationBeforeFCP() const {
   return millisecondsToSeconds(
       m_private->timing()->authorStyleSheetParseDurationBeforeFCP());
 }
 
+double WebPerformance::updateStyleDurationBeforeFCP() const {
+  return millisecondsToSeconds(
+      m_private->timing()->updateStyleDurationBeforeFCP());
+}
+
 WebPerformance::WebPerformance(Performance* performance)
     : m_private(performance) {}
 
 WebPerformance& WebPerformance::operator=(Performance* performance) {
   m_private = performance;
   return *this;
 }
 
 }  // namespace blink