service worker: Add promise boilerplate for NavigationPreload enable/disable

third_party/WebKit/Source/modules/serviceworkers/NavigationPreloadCallbacks.h

+// Copyright 2016 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 NavigationPreloadCallbacks_h
+#define NavigationPreloadCallbacks_h
+
+#include "public/platform/modules/serviceworker/WebServiceWorkerRegistration.h"
+
+namespace blink {
+
+class ScriptPromiseResolver;
+struct WebServiceWorkerError;
+
+class EnableNavigationPreloadCallbacks final

[nhiroki, 2016/10/13 11:29:13]

Why don't you use PromiseCallbackAdapter<void, ServiceWorkerError>? (see
following links)

https://cs.chromium.org/chromium/src/third_party/WebKit/Source/bindings/core/...
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/modules/servic...

[falken, 2016/10/14 04:08:50]

Yea I considered using PromiseCallbackAdapter but I never really understood it
and it seemed simpler to just write things out. Now having written this out I
can see how it'd be useful to avoid a new file and new classes. I'll consider
using it.

+    : public WebServiceWorkerRegistration::WebEnableNavigationPreloadCallbacks {
+ public:
+  EnableNavigationPreloadCallbacks(ScriptPromiseResolver*);
+  ~EnableNavigationPreloadCallbacks() override;
+
+  // WebEnableNavigationPreloadCallbacks interface.
+  void onSuccess() override;
+  void onError(const WebServiceWorkerError&) override;
+
+ private:
+  Persistent<ScriptPromiseResolver> m_resolver;
+  WTF_MAKE_NONCOPYABLE(EnableNavigationPreloadCallbacks);
+};
+
+class DisableNavigationPreloadCallbacks final

[nhiroki, 2016/10/13 11:29:13]

ditto.

+    : public WebServiceWorkerRegistration::
+          WebDisableNavigationPreloadCallbacks {
+ public:
+  DisableNavigationPreloadCallbacks(ScriptPromiseResolver*);
+  ~DisableNavigationPreloadCallbacks() override;
+
+  // WebDisableNavigationPreloadCallbacks interface.
+  void onSuccess() override;
+  void onError(const WebServiceWorkerError&) override;
+
+ private:
+  Persistent<ScriptPromiseResolver> m_resolver;
+  WTF_MAKE_NONCOPYABLE(DisableNavigationPreloadCallbacks);
+};
+
+}  // namespace blink
+
+#endif  // NavigationPreloadCallbacks_h