Add IDL and initial Blink API for Background Sync

Source/modules/background_sync/SyncRegistrationCallbacks.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// 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 PushSubscriptionCallbacks_h
-#define PushSubscriptionCallbacks_h
+#ifndef SyncRegistrationCallbacks_h
+#define SyncRegistrationCallbacks_h
 
 #include "platform/heap/Handle.h"
 #include "public/platform/WebCallbacks.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class ServiceWorkerRegistration;
 class ScriptPromiseResolver;
-struct WebPushError;
-struct WebPushSubscription;
+struct WebSyncError;
+struct WebSyncRegistration;
 
-// PushSubscriptionCallbacks is an implementation of WebPushSubscriptionCallbacks
+// SyncRegistrationCallbacks is an implementation of WebSyncRegistrationCallbacks
 // that will resolve the underlying promise depending on the result passed to
 // the callback. It takes a ServiceWorkerRegistration in its constructor and
-// will pass it to the PushSubscription.
-class PushSubscriptionCallbacks final : public WebCallbacks<WebPushSubscription, WebPushError> {
-    WTF_MAKE_NONCOPYABLE(PushSubscriptionCallbacks);
+// will pass it to the SyncProvider.
+class SyncRegistrationCallbacks final : public WebCallbacks<WebSyncRegistration, WebSyncError> {
+    WTF_MAKE_NONCOPYABLE(SyncRegistrationCallbacks);
 public:
-    PushSubscriptionCallbacks(PassRefPtrWillBeRawPtr<ScriptPromiseResolver>, ServiceWorkerRegistration*);
-    ~PushSubscriptionCallbacks() override;
+    SyncRegistrationCallbacks(PassRefPtrWillBeRawPtr<ScriptPromiseResolver>, ServiceWorkerRegistration*);
+    ~SyncRegistrationCallbacks() override;
 
-    void onSuccess(WebPushSubscription*) override;
-    void onError(WebPushError*) override;
+    void onSuccess(WebSyncRegistration*) override;
+    void onError(WebSyncError*) override;
 
 private:
     RefPtrWillBePersistent<ScriptPromiseResolver> m_resolver;
+    Persistent<ServiceWorkerRegistration> m_serviceWorkerRegistration;
+};
+
+// SyncUnregistrationCallbacks is an implementation of
+// WebSyncUnregistrationCallbacks that will resolve the underlying promise
+// depending on the result passed to the callback. It takes a
+// ServiceWorkerRegistration in its constructor and will pass it to the
+// SyncProvider.
+class SyncUnregistrationCallbacks final : public WebCallbacks<bool, WebSyncError> {
+    WTF_MAKE_NONCOPYABLE(SyncUnregistrationCallbacks);
+public:
+    SyncUnregistrationCallbacks(PassRefPtrWillBeRawPtr<ScriptPromiseResolver>, ServiceWorkerRegistration*);
+    ~SyncUnregistrationCallbacks() override;
+
+    void onSuccess(bool*) override;
+    void onError(WebSyncError*) override;
+
+private:
+    RefPtrWillBePersistent<ScriptPromiseResolver> m_resolver;
     Persistent<ServiceWorkerRegistration> m_serviceWorkerRegistration;
 };
 
 } // namespace blink
 
-#endif // PushSubscriptionCallbacks_h
+#endif // SyncRegistrationCallbacks_h