Introduce KeepAliveWhilePending to ScriptPromiseResolverWithContext.

Source/core/dom/AsyncInitializerContext.h

Index: Source/core/dom/AsyncInitializerContext.h
diff --git a/Source/core/dom/AsyncInitializerContext.h b/Source/core/dom/AsyncInitializerContext.h
new file mode 100644
index 0000000000000000000000000000000000000000..44112d343e860864e2831d8c543ef8c3b81f281a
--- /dev/null
+++ b/Source/core/dom/AsyncInitializerContext.h
@@ -0,0 +1,18 @@
+// Copyright 2014 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.
+
+#ifndef AsyncInitializerContext_h
+#define AsyncInitializerContext_h
+
+#include "platform/LifecycleContext.h"
+
+namespace WebCore {
+
+// AsyncInitializerContext is the LifeCycleContext for AsyncInitializer.
+class AsyncInitializerContext : public LifecycleContext<AsyncInitializerContext> {
+};
+
+} // namespace WebCore
+
+#endif // #ifndef AsyncInitializerContext_h