sync: final pieces to sync deferred initialization

chrome/browser/sync/startup_controller.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 CHROME_BROWSER_SYNC_STARTUP_CONTROLLER_H_
+#define CHROME_BROWSER_SYNC_STARTUP_CONTROLLER_H_
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "sync/internal_api/public/base/model_type.h"
+
+class ManagedUserSigninManagerWrapper;
+class ProfileOAuth2TokenService;
+
+namespace browser_sync {
+
+class SyncPrefs;
+
+// Defines the type of behavior the sync engine should use. If configured for
+// AUTO_START, the sync engine will automatically call SetSyncSetupCompleted()
+// and start downloading data types as soon as sync credentials are available.
+// If configured for MANUAL_START, sync will not start until the user
+// completes sync setup, at which point the UI makes an explicit call to
+// complete sync setup.
+enum ProfileSyncServiceStartBehavior {
+  AUTO_START,
+  MANUAL_START,
+};
+
+// This class is used by ProfileSyncService to manage all logic and state
+// pertaining to initialization of the SyncBackendHost (colloquially referred
+// to as "the backend").
+class StartupController {
+ public:
+  StartupController(ProfileSyncServiceStartBehavior start_behavior,
+                    ProfileOAuth2TokenService* token_service,
+                    const browser_sync::SyncPrefs* sync_prefs,
+                    const ManagedUserSigninManagerWrapper* signin,
+                    base::Closure start_backend);
+  ~StartupController();
+
+  // Starts up sync if it is not suppressed and preconditions are met.
+  // Returns true if these preconditions are met, although does not imply
+  // the backend was started.
+  bool TryStart();
+
+  // Called when a datatype (SyncableService) has a need for sync to start
+  // ASAP, presumably because a local change event has occurred but we're
+  // still in deferred start mode, meaning the SyncableService hasn't been
+  // told to MergeDataAndStartSyncing yet.
+  // It is expected that |type| is a currently active datatype.
+  void OnDataTypeRequestsSyncStartup(syncer::ModelType type);
+
+  // Prepares this object for a new attempt to start sync, forgetting
+  // whether or not preconditions were previously met.
+  void Reset();
+
+  void set_setup_in_progress(bool in_progress);
+  bool setup_in_progress() const { return setup_in_progress_; }
+  bool auto_start_enabled() const { return auto_start_enabled_; }
+  base::Time start_backend_time() const { return start_backend_time_; }
+  std::string GetBackendInitializationStateString() const;
+
+  void OverrideFallbackTimeoutForTest(const base::TimeDelta& timeout);
+ private:
+  enum StartUpDeferredOption {
+    STARTUP_BACKEND_DEFERRED,
+    STARTUP_IMMEDIATE
+  };
+  // Returns true if all conditions to start the backend are met.
+  bool StartUp(StartUpDeferredOption deferred_option);
+  void OnFallbackStartupTimerExpired();
+
+  // True if we should start sync ASAP because either a SyncableService has
+  // requested it, or we're done waiting for a sign and decided to go ahead.
+  bool received_start_request_;
+
+  // The time that StartUp() is called. This is used to calculate time spent
+  // in the deferred state; that is, after StartUp and before invoking the
+  // start_backend_ callback.
+  base::Time start_up_time_;
+
+  // If |true|, there is setup UI visible so we should not start downloading
+  // data types.
+  bool setup_in_progress_;
+
+  // If true, we want to automatically start sync signin whenever we have
+  // credentials (user doesn't need to go through the startup flow). This is
+  // typically enabled on platforms (like ChromeOS) that have their own
+  // distinct signin flow.
+  const bool auto_start_enabled_;
+
+  const browser_sync::SyncPrefs* sync_prefs_;
+
+  ProfileOAuth2TokenService* token_service_;
+
+  const ManagedUserSigninManagerWrapper* signin_;
+
+  // The callback we invoke when it's time to call expensive
+  // startup routines for the sync backend.
+  base::Closure start_backend_;
+
+  // The time at which we invoked the start_backend_ callback.
+  base::Time start_backend_time_;
+
+  base::TimeDelta fallback_timeout_;
+
+  base::WeakPtrFactory<StartupController> weak_factory_;
+};
+
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_STARTUP_CONTROLLER_H_