Remove metrics for XMLHttpRequest.send(ArrayBuffer).

Using an ArrayBuffer as the argument to XMLHttpRequest.send() is no
longer deprecated in the latest WHATWG spec, according to
https://www.w3.org/Bugs/Public/show_bug.cgi?id=26153#c1

This change removes the metrics used by the deprecation process. The
deprecation warnings will be removed in the Blink-side CL below.
https://codereview.chromium.org/373023002/

BUG=237493
NOTRY=true

Review URL: https://codereview.chromium.org/372223002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281956 0039d316-1c4b-4281-b951-d872f2087c98

tools/metrics/histograms/histograms.xml

@@ -34079,7 +34079,14 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="WebCore.XHR.send.ArrayBufferOrView"
     enum="XMLHttpRequestSendArrayBufferOrView">
-  <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
+  <obsolete>
+    Deprecated as of 7/2014. This histogram was used to determine when it would
+    be ok to remove the deprecated XMLHttpRequest.send(ArrayBuffer) overload.
+    The support for ArrayBuffer was un-deprecated in the WHATWG spec for XHR,
+    and subsequently un-deprecated in Blink.
+  </obsolete>
+  <owner>tyoshino@chromium.org</owner>
+  <owner>costan@gmail.com</owner>
   <summary>
     Count the number of XHR.send() calls for each argument type to see when we
     can deprecate the ArrayBuffer type support.