service worker: use 200 OK for update requests even in the no update case

content/browser/service_worker/embedded_worker_instance.h

Index: content/browser/service_worker/embedded_worker_instance.h
diff --git a/content/browser/service_worker/embedded_worker_instance.h b/content/browser/service_worker/embedded_worker_instance.h
index edb8295756a988fece3575f652b4ad381fe493c4..2bcbaab09e0bcbbc0fa5fd927704c5ba7d27560e 100644
--- a/content/browser/service_worker/embedded_worker_instance.h
+++ b/content/browser/service_worker/embedded_worker_instance.h
@@ -100,18 +100,21 @@ class CONTENT_EXPORT EmbeddedWorkerInstance {
                                         int line_number,
                                         const GURL& source_url) {}
     // Returns false if the message is not handled by this listener.
-    virtual bool OnMessageReceived(const IPC::Message& message) = 0;
+    CONTENT_EXPORT virtual bool OnMessageReceived(const IPC::Message& message);
   };
 
   ~EmbeddedWorkerInstance();
 
   // Starts the worker. It is invalid to call this when the worker is not in
   // STOPPED status. |callback| is invoked after the worker script has been
-  // started and evaluated, or when an error occurs.
+  // started and evaluated, or when an error occurs. If |pause_after_download|
+  // is true, the worker pauses after loading until ResumeAfterDownload() is
+  // called.
   void Start(int64_t service_worker_version_id,
              const GURL& scope,
              const GURL& script_url,
-             const StatusCallback& callback);
+             const StatusCallback& callback,
+             bool pause_after_download = false);
 
   // Stops the worker. It is invalid to call this when the worker is
   // not in STARTING or RUNNING status.
@@ -129,6 +132,9 @@ class CONTENT_EXPORT EmbeddedWorkerInstance {
   // status.
   ServiceWorkerStatusCode SendMessage(const IPC::Message& message);
 
+  // Resumes the worker if it paused after download.
+  void ResumeAfterDownload();
+
   // Returns the ServiceRegistry for this worker. It is invalid to call this
   // when the worker is not in STARTING or RUNNING status.
   ServiceRegistry* GetServiceRegistry();