ServiceWorker: Wait for registration promise to resolve before changing states.

public/platform/WebServiceWorker.h

 /*
  * 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 35 matching lines @@
 class WebServiceWorker {
 public:
     virtual ~WebServiceWorker() { }
 
     // Sets ServiceWorkerProxy, with which callee can start making upcalls
     // to the ServiceWorker object via the client. This doesn't pass the
     // ownership to the callee, and the proxy's lifetime is same as that of
     // WebServiceWorker.
     virtual void setProxy(WebServiceWorkerProxy*) { }
 
+    // Sets the state. This should only be called by the WebServiceWorkerProxy.
+    virtual void setState(blink::WebServiceWorkerState) { }

[michaeln1, 2014/04/24 21:15:08]

This webkit api is kinda convoluted? The proxy has an onStateChanged(st) method
to inform blink, this class has both a setter for blink to inform chromium, and
a getter for blink to query chromium. Hmmm...

If all you're looking at is this api, you'd be left wondering wth is up with
this, who/what exactly is the purveyor of truth regarding this 'state' junk?

What if this was rearranged a little? Here's a mental model. The blink-side can
be ready for state change events, but initially it might not be ready. When its
not ready, the chrome-side will defer making state changes (and instead queue
them up), so WebServiceWorker::state() will not mutate and
WebServiceWorkerProxy::dispatchStateChangeEvent() will not be called. When the
blink-side becomes ready, the chrome-side flushes the queued up changes by
updating its internal state and calling dispatchStateChangeEvent() for each
queue change.

So a webkit api that looks closer to...

// State changes are queued up until the blink-side is ready for them.
bool WebServiceWorkerProxy::isReady()

// Lets the chromium-side know that the blink-side has become ready or
// perhaps toggled back to not ready.
bool WebServiceWorker::proxyReadyChanged();

[falken, 2014/04/25 01:13:11]

Good idea, things would be clearer this way and I think it should work. I'll
take a stab at it and see how it turns out.

+
     virtual WebURL scope() const { return WebURL(); }
     virtual WebURL url() const { return WebURL(); }
     virtual WebServiceWorkerState state() const { return WebServiceWorkerStateUnknown; }
 
     // Callee receives ownership of the passed vector.
     // FIXME: Blob refs should be passed to maintain ref counts. crbug.com/351753
     virtual void postMessage(const WebString&, WebMessagePortChannelArray*) { BLINK_ASSERT_NOT_REACHED(); }
 };
 
 }
 
 #endif // WebServiceWorker_h