Introduce use counters for Blink specific editing event usage

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 420 matching lines @@
         TextDecoderConstructor = 431,
         TextDecoderDecode= 432,
         FocusInOutEvent = 433,
         MouseEventMovementX = 434,
         MouseEventMovementY = 435,
         MixedContentTextTrack = 436,
         MixedContentRaw = 437,
         MixedContentImage = 438,
         MixedContentMedia = 439,
         DocumentFonts = 440,
+        // Editing related Blink specific events.

[tkent, 2014/06/11 01:05:48]

I don't think this comment is necessary.

[yosin_UTC9, 2014/06/11 02:23:20]

Done.

+        TextInputEventOnInput = 441,
+        TextInputEventOnTextArea = 442,
+        TextInputEventOnContentEditable= 443,
+        TextInputEventOnNotNode = 444,
+        WebkitBeforeTextInsertedOnInput = 445,
+        WebkitBeforeTextInsertedOnTextArea = 446,
+        WebkitBeforeTextInsertedOnContentEditable = 447,
+        WebkitBeforeTextInsertedOnNotNode = 448,
+        WebkitEditableContentChangedOnInput = 449,
+        WebkitEditableContentChangedOnTextArea = 450,
+        WebkitEditableContentChangedOnContentEditable = 451,
+        WebkitEditableContentChangedOnNotNode = 452,
         // 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 Document&, Feature);
     // This doesn't count for non-Document ExecutionContext.
@@ skipping 45 matching lines @@
 
     void updateMeasurements();
 
     OwnPtr<BitVector> m_countBits;
     BitVector m_CSSFeatureBits;
 };
 
 } // namespace WebCore
 
 #endif // UseCounter_h