Extend scrolling prediction histograms

Specifically extend:
- Event.Latency.ScrollUpdate.Touch.AverageLag.PredictionNegative
- Event.Latency.ScrollUpdate.Touch.AverageLag.PredictionPositive

There is ongoing work to improve scrolling prediction which will benefit
from having these heuristics to gauge improvements on.

Bug: 1165054
Change-Id: Ied3b8c48f8cdf8736ba26d28204e459039ffb775
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628135Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845229}

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

@@ -1091,7 +1091,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram
     name="Event.Latency.ScrollUpdate.Touch.AverageLag.PredictionNegative"
-    units="pixels" expires_after="M90">
+    units="pixels" expires_after="M97">
   <owner>flackr@chromium.org</owner>
   <owner>joalmei@microsoft.com</owner>
   <owner>input-dev@chromium.org</owner>
@@ -1113,7 +1113,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram
     name="Event.Latency.ScrollUpdate.Touch.AverageLag.PredictionPositive"
-    units="pixels" expires_after="M90">
+    units="pixels" expires_after="M97">
   <owner>flackr@chromium.org</owner>
   <owner>joalmei@microsoft.com</owner>
   <owner>input-dev@chromium.org</owner>