ServiceWorker: Prevent premature garbage collection on ServiceWorkerRegistration

Before this patch, the ServiceWorkerRegistration object could be garbage
collected prematurely and it caused renderer crash.

This change keeps the registration object alive until stop() is called, and
notifies WebServiceWorkerRegistration of the stop event.


BUG=396400
TEST=https://codereview.chromium.org/466723002/

Review URL: https://codereview.chromium.org/467133002

git-svn-id: svn://svn.chromium.org/blink/trunk@180265 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/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

third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerRegistration.h

@@ -63,11 +63,17 @@ private:
     static PassRefPtrWillBeRawPtr<ServiceWorkerRegistration> getOrCreate(ExecutionContext*, WebServiceWorkerRegistration*);
     ServiceWorkerRegistration(ExecutionContext*, PassOwnPtr<WebServiceWorkerRegistration>);
 
+    // ActiveDOMObject overrides.
+    virtual bool hasPendingActivity() const OVERRIDE;
+    virtual void stop() OVERRIDE;
+
     OwnPtr<WebServiceWorkerRegistration> m_outerRegistration;
     WebServiceWorkerProvider* m_provider;
     RefPtrWillBeMember<ServiceWorker> m_installing;
     RefPtrWillBeMember<ServiceWorker> m_waiting;
     RefPtrWillBeMember<ServiceWorker> m_active;
+
+    bool m_stopped;
 };
 
 } // namespace blink

third_party/WebKit/public/platform/WebServiceWorkerRegistration.h

@@ -17,6 +17,7 @@ public:
 
     virtual void setProxy(WebServiceWorkerRegistrationProxy*) { }
     virtual WebServiceWorkerRegistrationProxy* proxy() { return 0; }
+    virtual void proxyStopped() { }
 
     virtual WebURL scope() const { return WebURL(); }
 };