Add platform files for Background Sync API

public/platform/modules/background_sync/WebSyncClient.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 WebPushClient_h
-#define WebPushClient_h
+#ifndef WebSyncClient_h
+#define WebSyncClient_h
 
 #include "public/platform/WebCallbacks.h"
-#include "public/platform/modules/push_messaging/WebPushError.h"
+#include "public/platform/modules/background_sync/WebSyncError.h"
 
 namespace blink {
 
 class WebServiceWorkerRegistration;
-struct WebPushSubscription;
+struct WebSyncRegistration;
 
-using WebPushSubscriptionCallbacks = WebCallbacks<WebPushSubscription, WebPushError>;
-// FIXME: Remove when no longer used by the embedder - https://crbug.com/446883.
-using WebPushRegistrationCallbacks = WebPushSubscriptionCallbacks;
+using WebSyncRegistrationCallbacks = WebCallbacks<WebSyncRegistration, WebSyncError>;
 
-class WebPushClient {
+class WebSyncClient {
 public:
-    virtual ~WebPushClient() { }
+    virtual ~WebSyncClient() { }
 
     // Ownership of the WebServiceWorkerRegistration is not transferred.
     // Ownership of the callbacks is transferred to the client.
-    virtual void registerPushMessaging(WebServiceWorkerRegistration*, WebPushRegistrationCallbacks*) { BLINK_ASSERT_NOT_REACHED(); }
+    virtual void registerSync(WebServiceWorkerRegistration*, WebSyncRegistrationCallbacks*) { BLINK_ASSERT_NOT_REACHED(); }

[jochen (gone - plz use gerrit), 2015/02/24 10:23:55]

why not make them pure virtual?

[iclelland, 2015/02/24 13:33:42]

Done.

 };
 
 } // namespace blink
 
-#endif // WebPushClient_h
+#endif // WebSyncClient_h