Revert "MediaCapabilities: Temporarily CHECK that we don't save bad data"

This reverts commit aa028783.

Reason for revert: Downgrading CHECK to DCHECK. No crashes hit.

Original change's description:
> MediaCapabilities: Temporarily CHECK that we don't save bad data
>
> CHECK is very aggressive - saving bad data is generally not a show
> stopper (except for data that causes FLT_EXCEPTIONS on win). The idea
> is to let this sit in pre-beta channels for a bit and find out if there
> are any remaining ways we can cause corrutpion.
>
> TODO(me): revert this before beta promotion.
>
> Bug: 982009
> Change-Id: If2faf12e56a54bd7244f08aa940be2ace9781ca4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1855199
> Auto-Submit: Chrome Cunningham <chcunningham@chromium.org>
> Commit-Queue: Frank Liberato <liberato@chromium.org>
> Reviewed-by: Frank Liberato <liberato@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#704998}

TBR=chcunningham@chromium.org,liberato@chromium.org

Bug: 982009
Change-Id: Ia98547875444cfefc3f8178f5f9127c9a86d2f6d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1885074
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Reviewed-by: Frank Liberato <liberato@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710089}

media/capabilities/video_decode_stats_db_impl.cc

@@ -348,10 +348,7 @@ void VideoDecodeStatsDBImpl::WriteUpdatedEntry(
   // Make sure we never write bogus stats into the DB! While its possible the DB
   // may experience some corruption (disk), we should have detected that above
   // and discarded any bad data prior to this upcoming save.
-  // TODO(chcunningham): Make this a DCHECK before we cut M79 for stable. Its
-  // not a show stopper to have corrupt DB, so CHECK is too aggressive. We just
-  // want pre-stable channel users to verify we've eliminated any bugs.
-  CHECK(AreStatsUsable(stats_proto.get()));
+  DCHECK(AreStatsUsable(stats_proto.get()));
 
   // Push the update to the DB.
   using DBType = leveldb_proto::ProtoDatabase<DecodeStatsProto>;