Add Prerender type to NavigationType for nav timing 2

third_party/WebKit/Source/core/timing/PerformanceTiming.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 27 matching lines @@
 #include "core/dom/DocumentTiming.h"
 #include "core/frame/LocalFrame.h"
 #include "core/loader/DocumentLoadTiming.h"
 #include "core/loader/DocumentLoader.h"
 #include "core/loader/FrameLoader.h"
 #include "core/paint/PaintTiming.h"
 #include "core/timing/PerformanceBase.h"
 #include "platform/network/ResourceLoadTiming.h"
 #include "platform/network/ResourceResponse.h"
 
+// Legacy support for NT1(https://www.w3.org/TR/navigation-timing/).
 namespace blink {
 
 static unsigned long long toIntegerMilliseconds(double seconds) {
   ASSERT(seconds >= 0);
   double clampedSeconds = PerformanceBase::clampTimeResolution(seconds);
   return static_cast<unsigned long long>(clampedSeconds * 1000.0);
 }
 
 static double toDoubleSeconds(unsigned long long integerMilliseconds) {
   return integerMilliseconds / 1000.0;
@@ skipping 468 matching lines @@
 
   return timing->pseudoWallTimeToMonotonicTime(
       toDoubleSeconds(integerMilliseconds));
 }
 
 DEFINE_TRACE(PerformanceTiming) {
   DOMWindowProperty::trace(visitor);
 }
 
 }  // namespace blink