Create ServiceWorkerProviderHost before starting worker

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 737417c88ce30130b965a300a4ade9502c079d02..8dbae220dcfa574d7d1d348a3b5bf50c35cadc4a 100644
--- a/content/browser/service_worker/embedded_worker_instance.h
+++ b/content/browser/service_worker/embedded_worker_instance.h
@@ -228,7 +228,7 @@ class CONTENT_EXPORT EmbeddedWorkerInstance
   void OnScriptLoaded() override;
   // Notifies the corresponding provider host that the thread has started and is
   // ready to receive messages.
-  void OnThreadStarted(int thread_id, int provider_id) override;
+  void OnThreadStarted(int thread_id) override;
   void OnScriptLoadFailed() override;
   // Fires the callback passed to Start().
   void OnScriptEvaluated(bool success) override;
@@ -283,7 +283,10 @@ class CONTENT_EXPORT EmbeddedWorkerInstance
   std::unique_ptr<EmbeddedWorkerInstance::WorkerProcessHandle> process_handle_;
   int thread_id_;
 
-  // |client_| is used to send messages to the renderer process.
+  // |client_| is used to send messages to the renderer process. This should not
+  // disconnected from the browser side manually because the pipe is possible to
+  // be used by other associated interfaces before disconnected from the
+  // renderer side.

[falken, 2017/06/06 14:06:33]

Not sure I understand. Does this mean the browser side should never disconnect
the pipe, and instead it's the renderer's responsibility to disconnect it?

If so, I'd suggest:
"The browser process should not disconnect the pipe, because other associated
interfaces may be using it. The renderer process will disconnect the pipe when
appropriate."

[shimazu, 2017/06/12 06:08:12]

Yes, that's correct. Updated, thanks!

   mojom::EmbeddedWorkerInstanceClientPtr client_;
 
   // Binding for EmbeddedWorkerInstanceHost, runs on IO thread.