Teach EmbeddedWorkerInstance to create a process when it needs one.

content/browser/service_worker/service_worker_dispatcher_host.h

 // Copyright 2013 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DISPATCHER_HOST_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DISPATCHER_HOST_H_
 
 #include "base/id_map.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string16.h"
@@ skipping 13 matching lines @@
 class ServiceWorkerRegistration;
 
 class CONTENT_EXPORT ServiceWorkerDispatcherHost : public BrowserMessageFilter {
  public:
   ServiceWorkerDispatcherHost(
       int render_process_id,
       MessagePortMessageFilter* message_port_message_filter);
 
   void Init(ServiceWorkerContextWrapper* context_wrapper);
 
-  // BrowserIOMessageFilter implementation
+  // BrowserMessageFilter implementation
+  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE;
   virtual void OnDestruct() const OVERRIDE;
   virtual bool OnMessageReceived(const IPC::Message& message,
                                  bool* message_was_ok) OVERRIDE;
 
+  // IPC::Sender implementation
+
+  // Send() queues the message until the underlying channel is ready.  This
+  // class assumes that Send() can only fail after that when the renderer
+  // process has terminated, at which point the whole instance will eventually
+  // be destroyed.
+  virtual bool Send(IPC::Message* message) OVERRIDE;
+
   void RegisterServiceWorkerHandle(scoped_ptr<ServiceWorkerHandle> handle);
 
  protected:
   virtual ~ServiceWorkerDispatcherHost();
 
  private:
   friend class BrowserThread;
   friend class base::DeleteHelper<ServiceWorkerDispatcherHost>;
   friend class TestingServiceWorkerDispatcherHost;
 
@@ skipping 42 matching lines @@
   void SendRegistrationError(int thread_id,
                              int request_id,
                              ServiceWorkerStatusCode status);
 
   int render_process_id_;
   MessagePortMessageFilter* const message_port_message_filter_;
   base::WeakPtr<ServiceWorkerContextCore> context_;
 
   IDMap<ServiceWorkerHandle, IDMapOwnPointer> handles_;
 
+  bool channel_ready_;  // True after BrowserMessageFilter::channel_ != NULL.
+  ScopedVector<IPC::Message> pending_messages_;
+
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerDispatcherHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DISPATCHER_HOST_H_