[GCM] Add support for canary connection attempts

google_apis/gcm/engine/connection_factory_impl.h

 // Copyright (c) 2013 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 GOOGLE_APIS_GCM_ENGINE_CONNECTION_FACTORY_IMPL_H_
 #define GOOGLE_APIS_GCM_ENGINE_CONNECTION_FACTORY_IMPL_H_
 
 #include "google_apis/gcm/engine/connection_factory.h"
 
 #include "base/memory/weak_ptr.h"
@@ skipping 57 matching lines @@
 
   // Helper method for initalizing the connection hander.
   // Virtual for testing.
   virtual void InitHandler();
 
   // Helper method for creating a backoff entry.
   // Virtual for testing.
   virtual scoped_ptr<net::BackoffEntry> CreateBackoffEntry(
       const net::BackoffEntry::Policy* const policy);
 
+  // Helper method for creating the connection handler.
+  // Virtual for testing.
+  virtual scoped_ptr<ConnectionHandler> CreateConnectionHandler(
+      base::TimeDelta read_timeout,
+      const ConnectionHandler::ProtoReceivedCallback& read_callback,
+      const ConnectionHandler::ProtoSentCallback& write_callback,
+      const ConnectionHandler::ConnectionChangedCallback& connection_callback);
+
   // Returns the current time in Ticks.
   // Virtual for testing.
   virtual base::TimeTicks NowTicks();
 
   // Callback for Socket connection completion.
   void OnConnectDone(int result);
 
   // ConnectionHandler callback for connection issues.
   void ConnectionHandlerCallback(int result);
 
  private:
+  // Helper method for checking backoff and triggering a connection as
+  // necessary.
+  void ConnectWithBackoff();
+
   // Proxy resolution and connection functions.
   void OnProxyResolveDone(int status);
   void OnProxyConnectDone(int status);
   int ReconsiderProxyAfterError(int error);
   void ReportSuccessfulProxyConnection();
 
   void CloseSocket();
 
   // The MCS endpoints to make connections to, sorted in order of priority.
   const std::vector<GURL> mcs_endpoints_;
@@ skipping 15 matching lines @@
   // The current proxy info.
   net::ProxyInfo proxy_info_;
   // The handle to the socket for the current connection, if one exists.
   net::ClientSocketHandle socket_handle_;
   // Current backoff entry.
   scoped_ptr<net::BackoffEntry> backoff_entry_;
   // Backoff entry from previous connection attempt. Updated on each login
   // completion.
   scoped_ptr<net::BackoffEntry> previous_backoff_;
 
-  // Whether a connection attempt is currently in progress or we're in backoff
-  // waiting until the next connection attempt. |!connecting_| denotes
-  // steady state with an active connection.
+  // Whether a connection attempt is currently actively in progress.
   bool connecting_;
 
+  // Whether the client is waiting for backoff to finish before attempting to
+  // connect. Canary jobs are able to preempt connections pending backoff
+  // expiration.
+  bool waiting_for_backoff_;
+
   // Whether login successfully completed after the connection was established.
   // If a connection reset happens while attempting to log in, the current
   // backoff entry is reused (after incrementing with a new failure).
   bool logging_in_;
 
   // The time of the last login completion. Used for calculating whether to
   // restore a previous backoff entry and for measuring uptime.
   base::TimeTicks last_login_time_;
 
   // The current connection handler, if one exists.
-  scoped_ptr<ConnectionHandlerImpl> connection_handler_;
+  scoped_ptr<ConnectionHandler> connection_handler_;
 
   // Builder for generating new login requests.
   BuildLoginRequestCallback request_builder_;
 
   base::WeakPtrFactory<ConnectionFactoryImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ConnectionFactoryImpl);
 };
 
 }  // namespace gcm
 
 #endif  // GOOGLE_APIS_GCM_ENGINE_CONNECTION_FACTORY_IMPL_H_