Extend the ExternalProtocolDialog metrics expiry date.

This CL extends the metrics expiry date for
ChromeOS.Apps.ExternalProtocolDialog,
ChromeOS.Apps.ExternalProtocolDialog.Accept, and
ChromeOS.Apps.ExternalProtocolDialog.Rejected.

BUG=1138256

Change-Id: I77d8fe378040c2448ee1d76f94b85a7c4674399b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2533217Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827074}

tools/metrics/histograms/histograms_xml/chromeos/histograms.xml

@@ -23,7 +23,7 @@ incoming reviews. Googlers can read more about this at go/gwsq-gerrit.
 <histograms>
 
 <histogram name="ChromeOS.Apps.ExternalProtocolDialog"
-    enum="ArcIntentHandlerAction" expires_after="M88">
+    enum="ArcIntentHandlerAction" expires_after="M90">
   <owner>dominickn@chromium.org</owner>
   <owner>melzhang@chromium.org</owner>
   <owner>mxcai@chromium.org</owner>
@@ -34,7 +34,7 @@ incoming reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="ChromeOS.Apps.ExternalProtocolDialog.Accepted"
-    enum="ArcExternalProtocolAction" expires_after="M88">
+    enum="ArcExternalProtocolAction" expires_after="M90">
   <owner>dominickn@chromium.org</owner>
   <owner>melzhang@chromium.org</owner>
   <owner>mxcai@chromium.org</owner>
@@ -46,7 +46,7 @@ incoming reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="ChromeOS.Apps.ExternalProtocolDialog.Rejected"
-    enum="ArcExternalProtocolAction" expires_after="M88">
+    enum="ArcExternalProtocolAction" expires_after="M90">
   <owner>dominickn@chromium.org</owner>
   <owner>melzhang@chromium.org</owner>
   <owner>mxcai@chromium.org</owner>