Extend the life of Android.OmniboxFocusReason histogram.

Bug: 1158456
Change-Id: I83141e1deffceef81e0e9d1928834dfe3f0783cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2596252
Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840399}

tools/metrics/histograms/histograms_xml/android/histograms.xml

@@ -1599,7 +1599,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Android.OmniboxFocusReason" enum="OmniboxFocusReason"
-    expires_after="2021-01-24">
+    expires_after="2021-12-01">
   <owner>mdjones@chromium.org</owner>
   <owner>twellington@chromium.org</owner>
   <owner>amaralp@chromium.org</owner>