Add NULL check of ExecutionContext in ServiceWorkerContainer

Source/modules/serviceworkers/ServiceWorkerContainer.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 116 matching lines @@
     ASSERT(RuntimeEnabledFeatures::serviceWorkerEnabled());
     RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
     if (!m_provider) {
         resolver->reject(DOMException::create(InvalidStateError, "Failed to register a ServiceWorker: The document is in an invalid state."));
         return promise;
     }
 
     ExecutionContext* executionContext = scriptState->executionContext();
+    // FIXME: May be null due to worker termination: http://crbug.com/413518.
+    if (!executionContext)
+        return ScriptPromise();
+
     RefPtr<SecurityOrigin> documentOrigin = executionContext->securityOrigin();
     String errorMessage;
     if (!executionContext->isPrivilegedContext(errorMessage)) {
         resolver->reject(DOMException::create(NotSupportedError, errorMessage));
         return promise;
     }
 
     KURL pageURL = KURL(KURL(), documentOrigin->toString());
     if (!pageURL.protocolIsInHTTPFamily()) {
         resolver->reject(DOMException::create(SecurityError, "Failed to register a ServiceWorker: The URL protocol of the current origin ('" + documentOrigin->toString() + "') is not supported."));
@@ skipping 39 matching lines @@
     ASSERT(RuntimeEnabledFeatures::serviceWorkerEnabled());
     RefPtrWillBeRawPtr<ScriptPromiseResolver> resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
 
     if (!m_provider) {
         resolver->reject(DOMException::create(InvalidStateError, "Failed to get a ServiceWorkerRegistration: The document is in an invalid state."));
         return promise;
     }
 
     ExecutionContext* executionContext = scriptState->executionContext();
+    // FIXME: May be null due to worker termination: http://crbug.com/413518.
+    if (!executionContext)
+        return ScriptPromise();
+
     RefPtr<SecurityOrigin> documentOrigin = executionContext->securityOrigin();
     String errorMessage;
     if (!executionContext->isPrivilegedContext(errorMessage)) {
         resolver->reject(DOMException::create(NotSupportedError, errorMessage));
         return promise;
     }
 
     KURL pageURL = KURL(KURL(), documentOrigin->toString());
     if (!pageURL.protocolIsInHTTPFamily()) {
         resolver->reject(DOMException::create(SecurityError, "Failed to get a ServiceWorkerRegistration: The URL protocol of the current origin ('" + documentOrigin->toString() + "') is not supported."));
@@ skipping 81 matching lines @@
         return;
 
     if (ServiceWorkerContainerClient* client = ServiceWorkerContainerClient::from(executionContext)) {
         m_provider = client->provider();
         if (m_provider)
             m_provider->setClient(this);
     }
 }
 
 } // namespace blink