Don't deref ChildThread::current() when null (it can be null in some tests)

content/renderer/render_frame_impl.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/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 
 #include "base/auto_reset.h"
@@ skipping 1359 matching lines @@
 blink::WebCookieJar* RenderFrameImpl::cookieJar(blink::WebLocalFrame* frame) {
   DCHECK(!frame_ || frame_ == frame);
   return &cookie_jar_;
 }
 
 blink::WebServiceWorkerProvider* RenderFrameImpl::createServiceWorkerProvider(
     blink::WebLocalFrame* frame) {
   DCHECK(!frame_ || frame_ == frame);
   // At this point we should have non-null data source.
   DCHECK(frame->dataSource());
+  if (!ChildThread::current())
+    return NULL;  // May be null in some tests.
   ServiceWorkerNetworkProvider* provider =
       ServiceWorkerNetworkProvider::FromDocumentState(
           DocumentState::FromDataSource(frame->dataSource()));
   int provider_id = provider ?
       provider->provider_id() :
       kInvalidServiceWorkerProviderId;
   return new WebServiceWorkerProviderImpl(
       ChildThread::current()->thread_safe_sender(), provider_id);
 }
 
@@ skipping 2003 matching lines @@
       weak_factory_.GetWeakPtr(),
       render_view_->media_player_manager_,
       stream_texture_factory,
       RenderThreadImpl::current()->GetMediaThreadMessageLoopProxy(),
       new RenderMediaLog());
 }
 
 #endif
 
 }  // namespace content