[Background Sync] Allow sync manager access from uncontrolled clients

public/platform/modules/background_sync/WebSyncProvider.h

Index: public/platform/modules/background_sync/WebSyncProvider.h
diff --git a/public/platform/modules/background_sync/WebSyncProvider.h b/public/platform/modules/background_sync/WebSyncProvider.h
index 36132b1a89730f8040a475ee81c0ffcbd18772e7..18dfb6720c00b1462916ceac6e97cb7cef17a7f0 100644
--- a/public/platform/modules/background_sync/WebSyncProvider.h
+++ b/public/platform/modules/background_sync/WebSyncProvider.h
@@ -29,7 +29,14 @@ public:
 
     // Takes ownership of the WebSyncRegistrationCallbacks.
     // Does not take ownership of the WebServiceWorkerRegistration.
-    virtual void registerBackgroundSync(const WebSyncRegistration*, WebServiceWorkerRegistration*, WebSyncRegistrationCallbacks*) = 0;
+    // TODO(iclelland): Remove the body of this method once it is implemented in all subclasses.
+    virtual void registerBackgroundSync(const WebSyncRegistration* options, WebServiceWorkerRegistration* serviceWorkerRegistration, bool requestedFromServiceWorker, WebSyncRegistrationCallbacks* callbacks)
+    {
+        registerBackgroundSync(options, serviceWorkerRegistration, callbacks);
+    }
+
+    // TODO(iclelland): Remove this deprecated method once callers have switched to the 4-argument version.

[jkarlin, 2015/08/26 12:45:41]

The callers have already switched in this case. Perhaps rephrase to "once the
browser implements the 4-argument version".

[iclelland, 2015/09/02 17:10:37]

That is, of course, absolutely correct :) Thanks; done.

+    virtual void registerBackgroundSync(const WebSyncRegistration*, WebServiceWorkerRegistration*, WebSyncRegistrationCallbacks*) { }
 
     // Takes ownership of the WebSyncUnregistrationCallbacks.
     // Does not take ownership of the WebServiceWorkerRegistration.