[DO NOT COMMIT] Set ServiceWorker initiated task highest priority

third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp

Index: third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
diff --git a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
index 0189baf843216e5c561f40f207c0cc740a7debcc..d99f7a0b97e94036a6c6735c0c9fe98ca83e8bd6 100644
--- a/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
+++ b/third_party/WebKit/Source/web/ServiceWorkerGlobalScopeProxy.cpp
@@ -61,6 +61,7 @@
 #include "modules/serviceworkers/ServiceWorkerWindowClient.h"
 #include "modules/serviceworkers/WaitUntilObserver.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/WebFrameScheduler.h"
 #include "public/platform/modules/notifications/WebNotificationData.h"
 #include "public/platform/modules/serviceworker/WebServiceWorkerEventResult.h"
 #include "public/platform/modules/serviceworker/WebServiceWorkerRequest.h"
@@ -468,7 +469,8 @@ ServiceWorkerGlobalScopeProxy::ServiceWorkerGlobalScopeProxy(
   // use the thread's default task runner. Note that |m_document| should not be
   // used as it's a dummy document for loading that doesn't represent the frame
   // of any associated document.
-  m_parentFrameTaskRunners = ParentFrameTaskRunners::create(nullptr);
+  m_parentFrameTaskRunners = ParentFrameTaskRunners::create(document.frame());
+  document.frame()->frameScheduler()->setMaximumPriorityForLabTest();
 }
 
 void ServiceWorkerGlobalScopeProxy::detach() {