Bypass ServiceWorkers for synchronous resource loads to avoid deadlocks when...

Bypass ServiceWorkers for synchronous resource loads to avoid deadlocks when the worker and page are running in the same process.

[1] this cl
[2] layout test https://codereview.chromium.org/573293005/

BUG=413103

Review URL: https://codereview.chromium.org/553333005

Cr-Commit-Position: refs/heads/master@{#297315}

content/browser/loader/resource_dispatcher_host_impl.cc

@@ -1138,14 +1138,15 @@ void ResourceDispatcherHostImpl::BeginRequest(
             new_request->url()));
   }
 
-  // Initialize the service worker handler for the request.
+  // Initialize the service worker handler for the request. We don't use
+  // ServiceWorker for synchronous loads to avoid renderer deadlocks.
   ServiceWorkerRequestHandler::InitializeHandler(
       new_request.get(),
       filter_->service_worker_context(),
       blob_context,
       child_id,
       request_data.service_worker_provider_id,
-      request_data.skip_service_worker,
+      request_data.skip_service_worker || is_sync_load,
       request_data.resource_type,
       request_data.request_body);