Simplify some CloudPrintProxy code.

chrome/service/cloud_print/cloud_print_proxy_backend.h

 // Copyright (c) 2012 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_SERVICE_CLOUD_PRINT_CLOUD_PRINT_PROXY_BACKEND_H_
 #define CHROME_SERVICE_CLOUD_PRINT_CLOUD_PRINT_PROXY_BACKEND_H_
 
 #include <list>
 #include <string>
 
@@ skipping 32 matching lines @@
   virtual void OnPrintSystemUnavailable() = 0;
   // Receive auth token and list of printers.
   virtual void OnUnregisterPrinters(
       const std::string& auth_token,
       const std::list<std::string>& printer_ids) = 0;
   // Update and store service settings.
   virtual void OnXmppPingUpdated(int ping_timeout) = 0;
 
  protected:
   // Don't delete through SyncFrontend interface.
-  virtual ~CloudPrintProxyFrontend() {
-  }
+  virtual ~CloudPrintProxyFrontend() {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(CloudPrintProxyFrontend);
 };
 
 class CloudPrintProxyBackend {
  public:
-  // It is OK for print_system_settings to be NULL. In this case system should
-  // use system default settings.
   CloudPrintProxyBackend(CloudPrintProxyFrontend* frontend,
                          const ConnectorSettings& settings,
                          const gaia::OAuthClientInfo& oauth_client_info,
                          bool enable_job_poll);
   ~CloudPrintProxyBackend();
 
   // Legacy mechanism when we have saved user credentials but no saved robot
   // credentials.
   bool InitializeWithToken(const std::string& cloud_print_token);
   // Called when we have saved robot credentials.
   bool InitializeWithRobotToken(const std::string& robot_oauth_refresh_token,
                                 const std::string& robot_email);
   // Called when an external entity passed in the auth code for the robot.
   bool InitializeWithRobotAuthCode(const std::string& robot_oauth_auth_code,
                                    const std::string& robot_email);
   void Shutdown();
   void RegisterPrinters(const printing::PrinterList& printer_list);
   void UnregisterPrinters();
 
  private:
+  bool PostCoreTask(const tracked_objects::Location& from_here,
+                    const base::Closure& task);
+
   // The real guts of SyncBackendHost, to keep the public client API clean.
   class Core;
-  // A thread we dedicate for use to perform initialization and
-  // authentication.
+
+  // A thread dedicated for use to perform initialization and authentication.
   base::Thread core_thread_;
-  // Our core, which communicates with AuthWatcher for GAIA authentication and
+
+  // The core, which communicates with AuthWatcher for GAIA authentication and
   // which contains printer registration code.
   scoped_refptr<Core> core_;
+
   // A reference to the MessageLoop used to construct |this|, so we know how
   // to safely talk back to the SyncFrontend.
   base::MessageLoop* const frontend_loop_;
-  // The frontend which is responsible for displaying UI and updating Prefs
-  CloudPrintProxyFrontend* frontend_;
+
+  // The frontend which is responsible for displaying UI and updating Prefs.
+  // Outlives this backend.
+  CloudPrintProxyFrontend* const frontend_;
 
   friend class base::RefCountedThreadSafe<CloudPrintProxyBackend::Core>;
 
   DISALLOW_COPY_AND_ASSIGN(CloudPrintProxyBackend);
 };
 
 }  // namespace cloud_print
 
 #endif  // CHROME_SERVICE_CLOUD_PRINT_CLOUD_PRINT_PROXY_BACKEND_H_