Enable per thread heap on SharedWorker

third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp

Index: third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp
diff --git a/third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp b/third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp
index d68b59581a9bbe4f8d69e55b2a9c20fab2086bf0..54cf81eebbc0c1435c55bcd768c5e1ab6481aa10 100644
--- a/third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp
+++ b/third_party/WebKit/Source/core/workers/SharedWorkerThread.cpp
@@ -45,7 +45,7 @@ std::unique_ptr<SharedWorkerThread> SharedWorkerThread::create(const String& nam
 
 SharedWorkerThread::SharedWorkerThread(const String& name, PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerReportingProxy& workerReportingProxy)
     : WorkerThread(std::move(workerLoaderProxy), workerReportingProxy)
-    , m_workerBackingThread(WorkerBackingThread::create("SharedWorker Thread", BlinkGC::MainThreadHeapMode))
+    , m_workerBackingThread(WorkerBackingThread::create("SharedWorker Thread", BlinkGC::PerThreadHeapMode))
     , m_name(name.isolatedCopy())
 {
 }