ServiceWorker: Prevent premature garbage collection on ServiceWorkerRegistration

Source/modules/serviceworkers/ServiceWorkerRegistration.cpp

Index: Source/modules/serviceworkers/ServiceWorkerRegistration.cpp
diff --git a/Source/modules/serviceworkers/ServiceWorkerRegistration.cpp b/Source/modules/serviceworkers/ServiceWorkerRegistration.cpp
index 455cf938f645e0b621a2c6ab62ad3218c7b28b06..b33fbda2c7f79aff26f2b10de9cd966da191f963 100644
--- a/Source/modules/serviceworkers/ServiceWorkerRegistration.cpp
+++ b/Source/modules/serviceworkers/ServiceWorkerRegistration.cpp
@@ -147,6 +147,7 @@ ServiceWorkerRegistration::ServiceWorkerRegistration(ExecutionContext* execution
     , WebServiceWorkerRegistrationProxy(this)
     , m_outerRegistration(outerRegistration)
     , m_provider(0)
+    , m_stopped(false)
 {
     ASSERT(m_outerRegistration);
     ScriptWrappable::init(this);
@@ -166,4 +167,17 @@ void ServiceWorkerRegistration::trace(Visitor* visitor)
     EventTargetWithInlineData::trace(visitor);
 }
 
+bool ServiceWorkerRegistration::hasPendingActivity() const
+{
+    return !m_stopped;
+}
+
+void ServiceWorkerRegistration::stop()
+{
+    if (m_stopped)
+        return;
+    m_stopped = true;
+    m_outerRegistration->proxyStopped();
+}
+
 } // namespace blink