CheckHasServiceWorkerCallback always called on the UI thread

content/browser/service_worker/service_worker_context_wrapper.cc

 // Copyright 2013 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.
 
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
 
 #include <map>
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 552 matching lines @@
     const GURL& other_url,
     const CheckHasServiceWorkerCallback& callback) {
   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
     BrowserThread::PostTask(
         BrowserThread::IO, FROM_HERE,
         base::Bind(&ServiceWorkerContextWrapper::CheckHasServiceWorker, this,
                    url, other_url, callback));
     return;
   }
   if (!context_core_) {
-    BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
                             base::Bind(callback, false));
     return;
   }
   context()->CheckHasServiceWorker(
       net::SimplifyUrlForRequest(url), net::SimplifyUrlForRequest(other_url),
       base::Bind(&ServiceWorkerContextWrapper::DidCheckHasServiceWorker, this,
                  callback));
 }
 
 void ServiceWorkerContextWrapper::CountExternalRequestsForTest(
@@ skipping 324 matching lines @@
   observer_list_->Notify(FROM_HERE,
                          &ServiceWorkerContextObserver::OnStorageWiped);
 }
 
 ServiceWorkerContextCore* ServiceWorkerContextWrapper::context() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   return context_core_.get();
 }
 
 }  // namespace content