Make DocumentLoader::timing return a reference

Source/core/workers/WorkerMessagingProxy.cpp

Index: Source/core/workers/WorkerMessagingProxy.cpp
diff --git a/Source/core/workers/WorkerMessagingProxy.cpp b/Source/core/workers/WorkerMessagingProxy.cpp
index 8935d1144f997f59df403a62bd573fbf15dcd266..efbca320a9db6240cc28ece6f45d5cc448447e5f 100644
--- a/Source/core/workers/WorkerMessagingProxy.cpp
+++ b/Source/core/workers/WorkerMessagingProxy.cpp
@@ -122,7 +122,7 @@ void WorkerMessagingProxy::startWorkerGlobalScope(const KURL& scriptURL, const S
     SecurityOrigin* starterOrigin = document->securityOrigin();
 
     OwnPtrWillBeRawPtr<WorkerThreadStartupData> startupData = WorkerThreadStartupData::create(scriptURL, userAgent, sourceCode, startMode, document->contentSecurityPolicy()->deprecatedHeader(), document->contentSecurityPolicy()->deprecatedHeaderType(), starterOrigin, m_workerClients.release());
-    double originTime = document->loader() ? document->loader()->timing()->referenceMonotonicTime() : monotonicallyIncreasingTime();
+    double originTime = document->loader() ? document->loader()->timing().referenceMonotonicTime() : monotonicallyIncreasingTime();
 
     m_loaderProxy = WorkerLoaderProxy::create(this);
     RefPtr<DedicatedWorkerThread> thread = DedicatedWorkerThread::create(m_loaderProxy, *m_workerObjectProxy.get(), originTime, startupData.release());