Web Audio: measure cross origin iframe usage.

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 1215 matching lines @@
         DocumentOpen = 1420,
         ElementRequestPointerLockInShadow = 1421,
         ShadowRootPointerLockElement = 1422,
         DocumentPointerLockElementInV0Shadow = 1423,
         TextAreaMaxLength = 1424,
         TextAreaMinLength = 1425,
         TopNavigationFromSubFrame = 1426,
         PrefixedElementRequestFullscreenInShadow = 1427,
         MediaSourceAbortRemove = 1428,
         MediaSourceDurationTruncatingBuffered = 1429,
+        AudioContextCrossOriginIframe = 1430,
 
         // 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 74 matching lines @@
     friend class UseCounterTest;
     static int m_muteCount;
 
     CountBits m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace blink
 
 #endif // UseCounter_h