[Background Sync] Add renderer code to interface between JS API and back-end service

content/child/background_sync/background_sync_provider_thread_proxy.h

+// Copyright 2015 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_CHILD_BACKGROUND_SYNC_BACKGROUND_SYNC_PROVIDER_THREAD_PROXY_H_
+#define CONTENT_CHILD_BACKGROUND_SYNC_BACKGROUND_SYNC_PROVIDER_THREAD_PROXY_H_
+
+#include "base/macros.h"
+#include "content/child/worker_task_runner.h"
+#include "third_party/WebKit/public/platform/modules/background_sync/WebSyncProvider.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace content {
+
+class BackgroundSyncProvider;
+
+// BackgroundSyncProviderThreadProxy is a proxy to the BackgroundSyncProvider
+// for callers running on a different thread than the main thread. There is one
+// instance of that class per thread.

[jkarlin, 2015/05/12 13:19:51]

s/of that class per thread/per worker thread/g

[iclelland, 2015/05/12 14:40:05]

Done.

+//
+// This class handles all of the thread switching, jumping to the main thread to
+// call the WebSyncProvider methods, and wrapping the callbacks passed in with
+// code to switch back to the original calling thread.
+class BackgroundSyncProviderThreadProxy :
+    public blink::WebSyncProvider,
+    public WorkerTaskRunner::Observer {
+
+ public:
+  static BackgroundSyncProviderThreadProxy* GetThreadInstance(
+      base::SingleThreadTaskRunner* main_thread_task_runner,
+      BackgroundSyncProvider* permissions_dispatcher);
+
+  // blink::WebSyncProvider implementation
+  void registerBackgroundSync(
+      const blink::WebSyncRegistration* options,
+      blink::WebServiceWorkerRegistration* service_worker_registration,
+      blink::WebSyncRegistrationCallbacks* callbacks);
+  void unregisterBackgroundSync(
+      blink::WebSyncRegistration::Periodicity periodicity,
+      int64_t id, const blink::WebString& tag,
+      blink::WebServiceWorkerRegistration* service_worker_registration,
+      blink::WebSyncUnregistrationCallbacks* callbacks);
+  void getRegistration(
+      blink::WebSyncRegistration::Periodicity,
+      const blink::WebString& tag,
+      blink::WebServiceWorkerRegistration* service_worker_registration,
+      blink::WebSyncRegistrationCallbacks* callbacks);
+  void getRegistrations(
+      blink::WebSyncRegistration::Periodicity periodicity,
+      blink::WebServiceWorkerRegistration* service_worker_registration,
+      blink::WebSyncGetRegistrationsCallbacks* callbacks);
+
+  // WorkerTaskRunner::Observer implementation.
+  void OnWorkerRunLoopStopped() override;
+
+ private:
+  BackgroundSyncProviderThreadProxy(
+      base::SingleThreadTaskRunner* main_thread_task_runner,
+      BackgroundSyncProvider* sync_provider);
+
+  virtual ~BackgroundSyncProviderThreadProxy();
+
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;

[jkarlin, 2015/05/12 13:19:51]

insert vertical space here so that you can more easily read the comment below?

[iclelland, 2015/05/12 14:40:05]

Done.

+  // This belongs to the renderer main thread, (created by BlinkPlatformImpl)
+  // and so should outlive the BackgroundSyncProviderThreadProxy, which is
+  // created for a worker thread.
+  BackgroundSyncProvider* sync_provider_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundSyncProviderThreadProxy);
+};
+
+}  // namespace content
+
+#endif // CONTENT_CHILD_BACKGROUND_SYNC_BACKGROUND_SYNC_PROVIDER_THREAD_PROXY_H_