Check WeakPtr validity in ServiceWorkerScriptLoaderFactory

Bug: 1129850
Change-Id: I1b1f7dbaa2f63fa7797cf9637a828e5379b7e39d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2428302
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Auto-Submit: Makoto Shimazu <shimazu@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810501}

content/browser/service_worker/service_worker_script_loader_factory.cc

@@ -229,6 +229,12 @@ void ServiceWorkerScriptLoaderFactory::OnCopyScriptFinished(
     mojo::PendingRemote<network::mojom::URLLoaderClient> client,
     int64_t new_resource_id,
     net::Error error) {
+  if (!worker_host_) {
+    // Null |worker_host_| means the worker has been terminated unexpectedly.
+    // Nothing can do in this case.
+    return;
+  }
+
   int64_t resource_size = cache_writer_->bytes_written();
   cache_writer_.reset();
   scoped_refptr<ServiceWorkerVersion> version = worker_host_->version();
@@ -268,6 +274,12 @@ void ServiceWorkerScriptLoaderFactory::OnResourceIdAssignedForNewScriptLoader(
     mojo::PendingRemote<network::mojom::URLLoaderClient> client,
     const net::MutableNetworkTrafficAnnotationTag& traffic_annotation,
     int64_t resource_id) {
+  if (!worker_host_) {
+    // Null |worker_host_| means the worker has been terminated unexpectedly.
+    // Nothing can do in this case.
+    return;
+  }
+
   if (resource_id == blink::mojom::kInvalidServiceWorkerResourceId) {
     mojo::Remote<network::mojom::URLLoaderClient>(std::move(client))
         ->OnComplete(network::URLLoaderCompletionStatus(net::ERR_ABORTED));