Extend histogram for AudioCodecProfile, xHE-AAC support is zero.

We haven't seen any usage of xHE-AAC yet, so extend the histogram
to ensure we have the data for making support plans.

Fixed: 1140052
Change-Id: Iec7df9916f216e9e2897f0916587c8f548cadf72
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2543182
Auto-Submit: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Dale Curtis <dalecurtis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828920}

tools/metrics/histograms/histograms_xml/media/histograms.xml

@@ -823,7 +823,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Media.AudioCodecProfile.AAC" enum="AudioCodecProfile"
-    expires_after="2020-12-01">
+    expires_after="2021-03-01">
   <owner>dalecurtis@chromium.org</owner>
   <owner>media-dev@chromium.org</owner>
   <summary>Audio codec profile used in HTML5 media for AAC playback.</summary>