Keep XHR progress throttle interval an implementation detail.

third_party/WebKit/Source/core/xmlhttprequest/XMLHttpRequestProgressEventThrottle.h

 /*
  * Copyright (C) 2010 Julien Chaffraix <jchaffraix@webkit.org>
  * All right reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 92 matching lines @@
         PassRefPtrWillBeRawPtr<Event> take();
 
     private:
         unsigned long long m_loaded;
         unsigned long long m_total;
         bool m_lengthComputable;
 
         bool m_isSet;
     };
 
-    static const double minimumProgressEventDispatchingIntervalInSeconds;
-
     void fired() override;
 
     Member<XMLHttpRequest> m_target;
 
     // A slot for the deferred "progress" ProgressEvent. When multiple events
     // arrive, only the last one is stored and others are discarded.
     DeferredEvent m_deferred;
 
     // True if any "progress" progress event has been dispatched since
     // |m_target|'s readyState changed.
     bool m_hasDispatchedProgressProgressEvent;
 };
 
 } // namespace blink
 
 #endif // XMLHttpRequestProgressEventThrottle_h