Extend histogram for delayed tap counts.

This extends the histogram Event.SingleTapType so that we can monitor
changes as we attempt to reduce the number of sites which have double
tap to zoom enabled.

Bug: 1088745
Change-Id: Ife06d0a4763924a3872754fdebbff63ad83abca0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2629867Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845217}

tools/metrics/histograms/histograms_xml/event/histograms.xml

@@ -1431,8 +1431,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
-<histogram name="Event.SingleTapType" enum="TapDelayType" expires_after="M85">
+<histogram name="Event.SingleTapType" enum="TapDelayType" expires_after="M97">
   <owner>flackr@chromium.org</owner>
+  <owner>input-dev@chromium.org</owner>
   <summary>
     On non-mobile sites, gesture taps are delayed to prevent double taps from
     sending a click event. This stat counts the number of taps that are delayed