Expose the ServiceWorker's v8 context to embedders.

public/web/WebServiceWorkerContextProxy.h

Index: public/web/WebServiceWorkerContextProxy.h
diff --git a/public/web/WebServiceWorkerContextProxy.h b/public/web/WebServiceWorkerContextProxy.h
index 6c6328d0bff08558f93467121aed29e30a8854f9..a53b90fb8685637a11cc4333f8a86d5d0a4c831d 100644
--- a/public/web/WebServiceWorkerContextProxy.h
+++ b/public/web/WebServiceWorkerContextProxy.h
@@ -33,6 +33,12 @@
 
 #include "public/platform/WebMessagePortChannel.h"
 
+namespace v8 {
+class Context;
+template <class T>
+class Handle;
+}
+
 namespace blink {
 
 class WebServiceWorkerRequest;
@@ -56,6 +62,11 @@ public:
     // Once the ServiceWorker has finished handling the sync event
     // didHandleSyncEvent is called on the context client.
     virtual void dispatchSyncEvent(int syncEventID) = 0;
+
+    // Returns the raw v8 context for the Service Worker. This must be called
+    // with an active HandleScope, and the handle is non-null in non-cleanup
+    // tasks from workerContextStarted() to willDestroyWorkerContext().
+    virtual v8::Handle<v8::Context> v8Context() = 0;
 };
 
 } // namespace blink