Activate the VariationsService for ChromeOS and ensure that it does not ping the server until the E…

chrome/browser/metrics/variations/resource_request_allowed_notifier.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[Nikita (slow), 2012/09/25 16:23:46]

Should ResourceRequestAllowedNotifier be moved to somewhere out of
chrome/browser/metrics/variations?

As far as I understand intention was to make it useful for other services as
well (like Translate).

[SteveT, 2012/09/25 18:49:11]

Again, it used to be under chrome/browser, but an early comment had me move it
here since we're the only consumer so far.

We will leave the fun of migrating it to the next user (of which there may be
many... we have to spend a bit of time investigating that to make sure we're
obeying the Eula).

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_METRICS_VARIATIONS_RESOURCE_REQUEST_ALLOWED_NOTIFIER_H_
+#define CHROME_BROWSER_METRICS_VARIATIONS_RESOURCE_REQUEST_ALLOWED_NOTIFIER_H_
+
+#include "base/observer_list.h"
+#include "net/base/network_change_notifier.h"
+
+#if defined(OS_CHROMEOS)
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#endif
+
+// This class informs an interested observer when resource requests over the
+// network are permitted.
+//
+// Currently, the criteria for allowing resource requests include:
+//  1. The network is currently available.
+//  2. The EULA was accepted by the user (ChromeOS only).
+//
+// Interested services should add themselves as an observer of
+// ResourceRequestAllowedNotifier and check ResourceRequestsAllowed() to see if
+// requests are permitted. If it returns true, they can go ahead and make their
+// request. If it returns false, ResourceRequestAllowedNotifier will notify the
+// service when the criteria is met.
+//
+// If ResourceRequestsAllowed returns true the first time,
+// ResourceRequestAllowedNotifier will not notify the service in the future.
+//
+// Note that this class handles the criteria state for a single service, so
+// services should keep their own instance of this class rather than sharing a
+// global instance.
+class ResourceRequestAllowedNotifier :
+#if defined(OS_CHROMEOS)
+    public content::NotificationObserver,
+#endif
+    public net::NetworkChangeNotifier::ConnectionTypeObserver {
+ public:
+  // Observes resource request allowed state changes.
+  class Observer {
+   public:
+    virtual void OnResourceRequestsAllowed() = 0;
+  };
+
+  ResourceRequestAllowedNotifier();
+  virtual ~ResourceRequestAllowedNotifier();
+
+  // Sets |observer| as the service to be notified by this instance, and
+  // performs initial checks on the criteria. |observer| may not be NULL.
+  // This is to be called immediately after construction of an instance of
+  // ResourceRequestAllowedNotifier to pass it the interested service.
+  void Init(Observer* observer);
+
+  // Returns true iff all resource request criteria are met. If not, this call
+  // will set some flags so it knows to notify the observer if the criteria
+  // changes. Note that the observer will never be notified unless it calls this
+  // method first. This is virtual so it can be overriden for tests.
+  virtual bool ResourceRequestsAllowed();
+
+  void SetWasWaitingForNetworkForTesting(bool waiting);
+#if defined(OS_CHROMEOS)
+  void SetWasWaitingForEulaForTesting(bool waiting);
+#endif
+
+ protected:
+  // Notifies the observer if all criteria needed for resource requests are met.
+  // This is protected so it can be called from subclasses for testing.
+  void MaybeNotifyObserver();
+
+#if defined(OS_CHROMEOS)
+  // On official builds, returns true iff the EULA needs to be accepted. This
+  // always returns false on unofficial builds since there is no notion of a
+  // EULA.
+  //
+  // This is virtual so it can be overriden by test classes to avoid making them
+  // aware of the ChromeOS details. This is protected so it call be overriden in
+  // subclasses for testing.
+  virtual bool NeedsEulaAcceptance();
+#endif
+
+ private:
+  // net::NetworkChangeNotifier::ConnectionTypeObserver overrides:
+  virtual void OnConnectionTypeChanged(
+      net::NetworkChangeNotifier::ConnectionType type) OVERRIDE;
+
+#if defined(OS_CHROMEOS)
+  // content::NotificationObserver overrides:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+#endif
+
+  // Tracks whether or not the observer/service depending on this class actually
+  // requested permission to make a request or not. If it did not, then this
+  // class should not notify it even if the criteria is met.
+  bool observer_requested_permission_;
+
+  // Tracks network connectivity criteria.
+  bool was_waiting_for_network_;
+
+#if defined(OS_CHROMEOS)
+  // Tracks EULA acceptance criteria.
+  bool was_waiting_for_user_to_accept_eula_;
+
+  // Used to listen for the EULA accepted notification.
+  content::NotificationRegistrar registrar_;
+#endif
+
+  // Observing service interested in request permissions.
+  Observer* observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResourceRequestAllowedNotifier);
+};
+
+#endif  // CHROME_BROWSER_METRICS_VARIATIONS_RESOURCE_REQUEST_ALLOWED_NOTIFIER_H_