Remove PageVisibilityObserver contextDestroyed() notifications.

third_party/WebKit/Source/modules/nfc/NFC.cpp

 // 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.
 
 #include "modules/nfc/NFC.h"
 
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8StringResource.h"
 #include "core/dom/DOMArrayBuffer.h"
@@ skipping 586 matching lines @@
 void NFC::dispose() {
   m_client.Close();
 }
 
 void NFC::contextDestroyed(ExecutionContext*) {
   m_nfc.reset();
   m_requests.clear();
   m_callbacks.clear();
 }
 
-void NFC::contextDestroyed(Page*) {}
-
 // https://w3c.github.io/web-nfc/#writing-or-pushing-content
 // https://w3c.github.io/web-nfc/#dom-nfc-push
 ScriptPromise NFC::push(ScriptState* scriptState,
                         const NFCPushMessage& pushMessage,
                         const NFCPushOptions& options) {
   ScriptPromise promise = rejectIfNotSupported(scriptState);
   if (!promise.isEmpty())
     return promise;
 
   DOMException* exception = isValidNFCPushMessage(pushMessage);
@@ skipping 201 matching lines @@
 }
 
 DEFINE_TRACE(NFC) {
   PageVisibilityObserver::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
   visitor->trace(m_requests);
   visitor->trace(m_callbacks);
 }
 
 }  // namespace blink