Add LayoutTests for the fixed multithread GC bug of ServiceWorker Navigation Preload

third_party/WebKit/Source/core/testing/WorkerInternals.cpp

 // Copyright 2016 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 "core/testing/WorkerInternals.h"
 
 #include "bindings/core/v8/ScriptState.h"
 #include "core/frame/Deprecation.h"
 #include "core/frame/UseCounter.h"
 #include "core/testing/OriginTrialsTest.h"
@@ skipping 12 matching lines @@
   UseCounter::count(scriptState->getExecutionContext(),
                     static_cast<UseCounter::Feature>(feature));
 }
 
 void WorkerInternals::countDeprecation(ScriptState* scriptState,
                                        uint32_t feature) {
   Deprecation::countDeprecation(scriptState->getExecutionContext(),
                                 static_cast<UseCounter::Feature>(feature));
 }
 
+void WorkerInternals::collectGarbage(ScriptState* scriptState) {
+  scriptState->isolate()->RequestGarbageCollectionForTesting(
+      v8::Isolate::kFullGarbageCollection);
+}
+
 }  // namespace blink