Remove ServiceWorkerObjectHost::version()

This isn't used.

Bug: N/A
Change-Id: Icf6f869a04b17bd2656ca05797092427fcb8657e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1955244
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#722406}

content/browser/service_worker/service_worker_object_host.h

@@ -80,8 +80,6 @@ class CONTENT_EXPORT ServiceWorkerObjectHost
           pending_object,
       blink::mojom::ServiceWorkerState sent_state);
 
-  ServiceWorkerVersion* version() { return version_.get(); }
-
   base::WeakPtr<ServiceWorkerObjectHost> AsWeakPtr();
 
  private: