Add use counter for chrome.loadTimes

third_party/WebKit/Source/core/frame/UseCounter.h

 /*
  * Copyright (C) 2012 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1241 matching lines @@
         SVGSMILAnimationAppliedEffect = 1477,
         PerformanceResourceTimingSizes = 1478,
         EventSourceDocument = 1479,
         EventSourceWorker = 1480,
         SingleOriginInTimingAllowOrigin = 1481,
         MultipleOriginsInTimingAllowOrigin = 1482,
         StarInTimingAllowOrigin = 1483,
         SVGSMILAdditiveAnimation = 1484,
         SendBeaconWithNonSimpleContentType = 1485,
 
+        ChromeLoadtimesRequestTime = 1486,
+        ChromeLoadtimesStartLoadTime = 1487,
+        ChromeLoadtimesCommitLoadTime = 1488,
+        ChromeLoadtimesFinishDocumentLoadTime = 1489,
+        ChromeLoadtimesFinishLoadTime = 1490,
+        ChromeLoadtimesFirstPaintTime = 1491,
+        ChromeLoadtimesFirstPaintAfterLoadTime = 1492,
+        ChromeLoadtimesNavigationType = 1493,
+        ChromeLoadtimesWasFetchedViaSpdy = 1494,
+        ChromeLoadtimesWasNpnNegotiated = 1495,
+        ChromeLoadtimesNpnNegotiatedProtocol = 1496,
+        ChromeLoadtimesWasAlternateProtocolAvailable = 1497,
+        ChromeLoadtimesConnectionInfo = 1498,

[esprehn, 2016/08/05 20:57:36]

So crazy we're this high on UseCounters now, I remember when we had like 200 of
them. :)

[panicker, 2016/08/05 23:06:14]

Interesting.
Curious - is deprecation the primary usecase here? If so I'd expect the list to
grow, but also shrink sometimes :)

[esprehn, 2016/08/05 23:07:52]

The list might shrink, but the numbers can never go down or it'd mess of the
historical UMA data. This enum will grow to infinity :)

+
         // Add new features immediately above this line. Don't change assigned
         // numbers of any item, and don't reuse removed slots.
         // Also, run update_use_counter_feature_enum.py in chromium/src/tools/metrics/histograms/
         // to update the UMA mapping.
         NumberOfFeatures, // This enum value must be last.
     };
 
     // "count" sets the bit for this feature to 1. Repeated calls are ignored.
     static void count(const Frame*, Feature);
     static void count(const Document&, Feature);
@@ skipping 73 matching lines @@
     friend class UseCounterTest;
     unsigned m_muteCount;
 
     CountBits m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace blink
 
 #endif // UseCounter_h