Extend expiry of Drive push notifications metrics

Bug: 1125669
Change-Id: Ia0de3d3be2fb1f91f49a1ec5cf07139625bdf924
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2426148
Commit-Queue: Sergei Datsenko <dats@chromium.org>
Reviewed-by: Austin Tankiang <austinct@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811117}

tools/metrics/histograms/histograms_xml/others/histograms.xml

@@ -4128,9 +4128,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Drive.PushNotificationInitiallyEnabled" enum="BooleanEnabled"
-    expires_after="M87">
-  <owner>slangley@chromium.org</owner>
-  <owner>weifangsun@chromium.org</owner>
+    expires_after="M91">
+  <owner>dats@chromium.org</owner>
+  <owner>austinct@chromium.org</owner>
   <summary>
     Tracks whether the push notification is initially enabled for Drive.
     Recorded when the first notification is processed. Notification is emulated
@@ -4139,9 +4139,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Drive.PushNotificationRegistered" enum="BooleanRegistered"
-    expires_after="M87">
-  <owner>slangley@chromium.org</owner>
-  <owner>weifangsun@chromium.org</owner>
+    expires_after="M91">
+  <owner>dats@chromium.org</owner>
+  <owner>austinct@chromium.org</owner>
   <summary>
     Tracks whether the push notification request is registered correctly for
     Drive. Recorded when the push notification manager is initialized.