Add usage counter to OffscreenCanvas API calls

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 1361 matching lines @@
     RTCPeerConnectionCreateDataChannelMaxRetransmitTime = 1648,
     RTCPeerConnectionCreateDataChannelMaxRetransmits = 1649,
     AudioContextCreateConstantSource = 1650,
     WebAudioConstantSourceNode = 1651,
     LoopbackEmbeddedInSecureContext = 1652,
     LoopbackEmbeddedInNonSecureContext = 1653,
     BlinkMacSystemFont = 1654,
     RTCConfigurationIceTransportsNone = 1655,
     RTCIceServerURL = 1656,
     RTCIceServerURLs = 1657,
+    OffscreenCanvasTransferToImageBitmap2D = 1658,
+    OffscreenCanvasTransferToImageBitmapWebGL = 1659,
+    OffscreenCanvasCommit2D = 1660,
+    OffscreenCanvasCommitWebGL = 1661,
 
     // 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);
@@ skipping 68 matching lines @@
     // Tracks what features/properties need to be reported to the legacy
     // histograms.
     BitVector m_featureBits;
     BitVector m_CSSBits;
   } m_legacyCounter;
 };
 
 }  // namespace blink
 
 #endif  // UseCounter_h