Add GCMChannelStatusRequest to talk with server for all users

components/gcm_driver/gcm_channel_status_request.h

+// Copyright 2014 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 COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_REQUEST_H_
+#define COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_REQUEST_H_
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "net/base/backoff_entry.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "net/url_request/url_request_context_getter.h"
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace gcm {
+
+// Defines the request to talk with the server to determine if the GCM support
+// should be enabled.
+class GCMChannelStatusRequest : public net::URLFetcherDelegate {
+ public:
+  // Callback completing the channel status request.
+  typedef base::Callback<void(bool enabled,
+                              const base::TimeDelta& poll_interval)>
+      GCMChannelStatusRequestCallback;
+
+  GCMChannelStatusRequest(
+      const std::string& client_id,

[Nicolas Zea, 2014/09/04 23:57:50]

What is client id going to be?

[jianli, 2014/09/05 18:41:55]

This is similar to GenerateCacheGUID or GenerateInvalidatorClientId. We can't
use the one that is created only for sync users. So here we just generate our
own one.

[Nicolas Zea, 2014/09/05 18:53:03]

Do we need a client id at all? If this is a kill switch, why do we need to
differentiate by client? Presumably UserAgent is enough?

[jianli, 2014/09/05 21:26:17]

After talking w/ Kevin, we don't need this.

+      scoped_refptr<net::URLRequestContextGetter> request_context_getter,

[Nicolas Zea, 2014/09/04 23:57:50]

nit: scoped_refptrs should be passed by const ref (const scoped_refptr<...>&)

[jianli, 2014/09/05 18:41:55]

Done.

+      const GCMChannelStatusRequestCallback& callback);
+  virtual ~GCMChannelStatusRequest();
+
+  void Start();
+
+  // Exposed for testing purpose.
+  static base::TimeDelta default_poll_interval_for_testing();
+  static base::TimeDelta min_poll_interval_for_testing();
+
+ private:
+  // Overridden from URLFetcherDelegate:
+  virtual void OnURLFetchComplete(const net::URLFetcher* source) OVERRIDE;
+
+  bool ParseResponse(const net::URLFetcher* source);
+  void RetryWithBackoff(bool update_backoff);
+
+  std::string client_id_;  // Our unique ID.

[Nicolas Zea, 2014/09/04 23:57:50]

nit: make const (and any other of these members than can be const)

[jianli, 2014/09/05 18:41:55]

Done.

+  scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
+  GCMChannelStatusRequestCallback callback_;
+  scoped_ptr<net::URLFetcher> url_fetcher_;
+  net::BackoffEntry backoff_entry_;
+  base::WeakPtrFactory<GCMChannelStatusRequest> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMChannelStatusRequest);
+};
+
+}  // namespace gcm
+
+#endif  // COMPONENTS_GCM_DRIVER_GCM_CHANNEL_STATUS_REQUEST_H_