Expand IOS.MainThreadFreezeDetection.RecoveredAfter

Bug: 1147716
Change-Id: Ia7f8bed3568088342ebdac56fbd7b6d4b1b9db03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537638
Auto-Submit: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827919}

tools/metrics/histograms/histograms_xml/ios/histograms.xml

@@ -413,7 +413,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="IOS.MainThreadFreezeDetection.RecoveredAfter" units="ms"
-    expires_after="2020-12-25">
+    expires_after="2021-11-12">
   <owner>eugenebut@chromium.org</owner>
   <owner>olivierrobin@chromium.org</owner>
   <summary>