[WIP] Support PerformanceResourceTiming for Service Worker Navigation Preload

third_party/WebKit/Source/core/timing/PerformanceBase.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel 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.
@@ skipping 487 matching lines @@
       observer->Deliver();
   }
 }
 
 // static
 double PerformanceBase::ClampTimeResolution(double time_seconds) {
   const double kResolutionSeconds = 0.000005;
   return floor(time_seconds / kResolutionSeconds) * kResolutionSeconds;
 }
 
+// static
 DOMHighResTimeStamp PerformanceBase::MonotonicTimeToDOMHighResTimeStamp(
     double time_origin,
-    double monotonic_time) {
+    double monotonic_time,
+    bool allow_negative_value) {
   // Avoid exposing raw platform timestamps.
   if (!monotonic_time || !time_origin)
     return 0.0;
 
   double time_in_seconds = monotonic_time - time_origin;
-  if (time_in_seconds < 0)
+  if (time_in_seconds < 0 && !allow_negative_value)
     return 0.0;
   return ConvertSecondsToDOMHighResTimeStamp(
       ClampTimeResolution(time_in_seconds));
 }
 
 DOMHighResTimeStamp PerformanceBase::MonotonicTimeToDOMHighResTimeStamp(
     double monotonic_time) const {
-  return MonotonicTimeToDOMHighResTimeStamp(time_origin_, monotonic_time);
+  return MonotonicTimeToDOMHighResTimeStamp(time_origin_, monotonic_time,
+                                            false /* allow_negative_value */);
 }
 
 DOMHighResTimeStamp PerformanceBase::now() const {
   return MonotonicTimeToDOMHighResTimeStamp(MonotonicallyIncreasingTime());
 }
 
 DEFINE_TRACE(PerformanceBase) {
   visitor->Trace(frame_timing_buffer_);
   visitor->Trace(resource_timing_buffer_);
   visitor->Trace(navigation_timing_);
   visitor->Trace(user_timing_);
   visitor->Trace(observers_);
   visitor->Trace(active_observers_);
   visitor->Trace(suspended_observers_);
   EventTargetWithInlineData::Trace(visitor);
 }
 
 }  // namespace blink