Fix race condition in content_shell which could lead to an assert on shutdown with PlzNavigate.

content/browser/loader/resource_dispatcher_host_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 
 #include <stddef.h>
 
@@ skipping 565 matching lines @@
     // browser-owned requests are the only requests that aren't cancelled when
     // the associated processes go away. It may be OK for this invariant to
     // change in the future, but if this assertion fires without the invariant
     // changing, then it's indicative of a leak.
     DCHECK(
         loader->GetRequestInfo()->IsDownload() ||
         loader->GetRequestInfo()->is_stream() ||
         (loader->GetRequestInfo()->detachable_handler() &&
          loader->GetRequestInfo()->detachable_handler()->is_detached()) ||
         loader->GetRequestInfo()->requester_info()->IsBrowserSideNavigation() ||
-        loader->is_transferring());
+        loader->is_transferring() ||
+        loader->GetRequestInfo()->GetResourceType() ==
+            RESOURCE_TYPE_SERVICE_WORKER);
   }
 #endif
 
   loaders_to_cancel.clear();
 
   if (async_revalidation_manager_) {
     // Cancelling async revalidations should not result in the creation of new
     // requests. Do it before the CHECKs to ensure this does not happen.
     async_revalidation_manager_->CancelAsyncRevalidationsForResourceContext(
         context);
@@ skipping 2195 matching lines @@
                                  &throttles);
     if (!throttles.empty()) {
       handler.reset(new ThrottlingResourceHandler(std::move(handler), request,
                                                   std::move(throttles)));
     }
   }
   return handler;
 }
 
 }  // namespace content