Document and measure the TextEvent interface and the textinput event

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 713 matching lines @@
         V8IDBRequest_Error_AttributeGetter = 820,
         V8IDBTransaction_Error_AttributeGetter = 821,
         V8DOMStringList_Item_Method = 822,
         V8Location_AncestorOrigins_AttributeGetter = 823,
         V8IDBDatabase_ObjectStoreNames_AttributeGetter = 824,
         V8IDBObjectStore_IndexNames_AttributeGetter = 825,
         V8IDBTransaction_ObjectStoreNames_AttributeGetter = 826,
         V8Navigator_GetStorageUpdates_Method = 827,
         V8TextTrackCueList_Item_Method = 828,
         V8TextTrackList_Item_Method = 829,
+        TextInputFired = 830,
+        V8TextEvent_Data_AttributeGetter = 831,
+        V8TextEvent_InitTextEvent_Method = 832,
 
         // 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 83 matching lines @@
 
     bool hasRecordedMeasurement(Feature feature) const { return m_countBits.hasRecordedMeasurement(feature); }
 
     CountBits m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace blink
 
 #endif // UseCounter_h