[bfcache] Change DCHECK to CHECK to fix crashes

This CL changes DCHECKs to CHECKs in ServiceWorkerVersion::Restore
ControlleeFromBackForwardCacheMap to figure out the cause of the
crashes.

Bug: 1021718
Change-Id: Ifdfe7772466b24ce18366d66895152b132b929c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2035529
Commit-Queue: Yuzu Saijo <yuzus@chromium.org>
Auto-Submit: Yuzu Saijo <yuzus@chromium.org>
Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738532}

content/browser/service_worker/service_worker_version.cc

@@ -798,10 +798,12 @@ void ServiceWorkerVersion::MoveControlleeToBackForwardCacheMap(
 
 void ServiceWorkerVersion::RestoreControlleeFromBackForwardCacheMap(
     const std::string& client_uuid) {
-  DCHECK(IsBackForwardCacheEnabled());
-  DCHECK(!base::Contains(controllee_map_, client_uuid));
-  DCHECK(base::Contains(bfcached_controllee_map_, client_uuid));
-  AddControllee(bfcached_controllee_map_[client_uuid]);
+  // TODO(crbug.com/1021718): Change these to DCHECK once we figure out the
+  // cause of crash.
+  CHECK(IsBackForwardCacheEnabled());
+  CHECK(!base::Contains(controllee_map_, client_uuid));
+  CHECK(base::Contains(bfcached_controllee_map_, client_uuid));
+  AddControllee(bfcached_controllee_map_.at(client_uuid));
   bfcached_controllee_map_.erase(client_uuid);
 }