Move content/child/background_sync to Blink.

third_party/WebKit/Source/modules/background_sync/BackgroundSyncProvider.h

+// Copyright 2016 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 BackgroundSyncProvider_h
+#define BackgroundSyncProvider_h
+
+#include "modules/background_sync/SyncCallbacks.h"
+#include "public/platform/modules/background_sync/background_sync.mojom-blink.h"
+#include "wtf/Noncopyable.h"
+
+namespace blink {
+
+class WebServiceWorkerRegistration;
+
+// The BackgroundSyncProvider is called by the SyncManager and SyncRegistration
+// objects and communicates with the BackgroundSyncManager object in the browser
+// process. Each thread will have its own instance (e.g. main thread, worker
+// threads), instantiated as needed by SyncManager.  Each instance of
+// the provider creates a new mojo connection to a new
+// BackgroundSyncManagerImpl, which then talks to the BackgroundSyncManager
+// object.

[iclelland, 2016/11/14 18:43:07]

Nit: re-wrap the paragraph

[adithyas, 2016/11/14 19:51:49]

Done.

+class BackgroundSyncProvider {
+  WTF_MAKE_NONCOPYABLE(BackgroundSyncProvider);
+
+ public:
+  BackgroundSyncProvider() = default;
+
+  void registerBackgroundSync(mojom::blink::SyncRegistrationPtr options,
+                              WebServiceWorkerRegistration*,
+                              std::unique_ptr<SyncRegistrationCallbacks>);

[iclelland, 2016/11/14 18:43:07]

I think you need to #include <memory> to get std::unique_ptr (you're probably
including it transitively, but it's not obvious from where)

[adithyas, 2016/11/14 19:51:49]

Done.

+  void getRegistrations(WebServiceWorkerRegistration*,
+                        std::unique_ptr<SyncGetRegistrationsCallbacks>);
+
+ private:
+  // Callback handlers
+  static void registerCallback(
+      std::unique_ptr<blink::SyncRegistrationCallbacks>,
+      mojom::blink::BackgroundSyncError,
+      mojom::blink::SyncRegistrationPtr options);
+  static void getRegistrationsCallback(
+      std::unique_ptr<SyncGetRegistrationsCallbacks>,
+      mojom::blink::BackgroundSyncError,
+      mojo::WTFArray<mojom::blink::SyncRegistrationPtr> registrations);
+
+  // Helper method that returns an initialized BackgroundSyncServicePtr.

[iclelland, 2016/11/14 18:43:07]

Can you mention here that it will connect to the browser's BackgroundSyncService
if necessary? (i.e., it's not just a simple getter for m_backgroundSyncService)

[adithyas, 2016/11/14 19:51:49]

Done.

+  mojom::blink::BackgroundSyncServicePtr& GetBackgroundSyncServicePtr();
+
+  mojom::blink::BackgroundSyncServicePtr m_backgroundSyncService;
+};
+
+}  // namespace blink
+
+#endif  // BackgroundSyncProvider_h