Background service worker push message processing

chrome/browser/push_messaging/background_budget_service.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 CHROME_BROWSER_PUSH_MESSAGING_BACKGROUND_BUDGET_SERVICE_H_
+#define CHROME_BROWSER_PUSH_MESSAGING_BACKGROUND_BUDGET_SERVICE_H_
+
+#include <string>
+
+#include "base/callback_forward.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "url/gurl.h"
+
+class Profile;
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+namespace chrome {
+
+// A budget service to help chrome decide how much background work a service
+// worker should be able to do on behalf of the user. The budget will be derived
+// from the Site engagement score for each domain, but in the initial
+// implementation it is just using the old grace period logic.

[Peter Beverloo, 2016/04/08 10:41:11]

Comment nits:
  - s/chrome/Chrome/.
  - "... will be ..., ... initial implementation ..." - the comment should
reflect what the code does *today*. Refer to a BUG in a TODO for functionality
that is yet to be added.

[harkness, 2016/04/08 14:11:43]

Done.

+// TODO(harkness) do I need a CHROME_EXPORT?

[Peter Beverloo, 2016/04/08 10:41:11]

No.

The *_EXPORT macros are used when building Chrome in component build, i.e. many
.so/.dll files rather than few. In these cases the linker needs to be told
whether functionality should be imported to or exported from the current build
target.

[harkness, 2016/04/08 14:11:43]

Acknowledged.

[Peter Beverloo, 2016/04/08 14:29:38]

So remove the TODO? :)

+class BackgroundBudgetService : public KeyedService {
+ public:
+  BackgroundBudgetService() {}
+  ~BackgroundBudgetService() override {}
+
+  void Shutdown() override {}
+
+  using BudgetCallback = base::Callback<void(bool success)>;

[Peter Beverloo, 2016/04/08 10:41:11]

Where would we use the success/failure callback of StoreBudget? How would we
behave differently when it fails?

[harkness, 2016/04/08 14:11:43]

Currently, this isn't used at all. I had it in this code because this was a
minimal change to the original code, but I think I'll pull out the callback
entirely.

+
+  using StringCallback = base::Callback<void(const std::string& data)>;

[Peter Beverloo, 2016/04/08 10:41:11]

nit: I'd call this BudgetCallback.

[harkness, 2016/04/08 14:11:43]

I'd actually already changed that in my next patch, but I'll move that change to
this one.

+
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
+  static void GetBudget(Profile* profile,

[Peter Beverloo, 2016/04/08 10:41:11]

Get/StoreBudget need to be documented. Today they store and retrieve whatever
string data you give them, but I'd hope that they get defined values in the
future. (E.g. a number?)

[harkness, 2016/04/08 14:11:43]

Done.

+                        const GURL& origin,
+                        const StringCallback& callback);
+
+  static void StoreBudget(Profile* profile,
+                          const GURL& origin,
+                          const std::string& notifications_shown,
+                          const BudgetCallback& callback);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_PUSH_MESSAGING_BACKGROUND_BUDGET_SERVICE_H_