Revert "Revert 142517 - [Sync] Refactor sync configuration logic."

sync/engine/sync_scheduler.h

Index: sync/engine/sync_scheduler.h
diff --git a/sync/engine/sync_scheduler.h b/sync/engine/sync_scheduler.h
index efe9789979ea906614a811783d555ec0a4b43257..3481d3e21b7c39ec9cf4a9c2f44847c578ab811d 100644
--- a/sync/engine/sync_scheduler.h
+++ b/sync/engine/sync_scheduler.h
@@ -37,6 +37,32 @@ namespace syncer {
 
 struct ServerConnectionEvent;
 
+struct ConfigurationParams {
+  enum KeystoreKeyStatus {
+    KEYSTORE_KEY_UNNECESSARY,
+    KEYSTORE_KEY_NEEDED
+  };
+  ConfigurationParams();
+  ConfigurationParams(
+      const sync_pb::GetUpdatesCallerInfo::GetUpdatesSource& source,
+      const syncer::ModelTypeSet& types_to_download,
+      const syncer::ModelSafeRoutingInfo& routing_info,
+      KeystoreKeyStatus keystore_key_status,
+      const base::Closure& ready_task);
+  ~ConfigurationParams();
+
+  // Source for the configuration.
+  sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source;
+  // The types that should be downloaded.
+  syncer::ModelTypeSet types_to_download;
+  // The new routing info (superset of types to be downloaded).
+  ModelSafeRoutingInfo routing_info;
+  // Whether we need to perform a GetKey command.
+  KeystoreKeyStatus keystore_key_status;
+  // Callback to invoke on configuration completion.
+  base::Closure ready_task;
+};
+
 class SyncScheduler : public sessions::SyncSession::Delegate {
  public:
   enum Mode {
@@ -63,10 +89,15 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
 
   // Start the scheduler with the given mode.  If the scheduler is
   // already started, switch to the given mode, although some
-  // scheduled tasks from the old mode may still run.  If non-NULL,
-  // |callback| will be invoked when the mode has been changed to
-  // |mode|.  Takes ownership of |callback|.
-  void Start(Mode mode, const base::Closure& callback);
+  // scheduled tasks from the old mode may still run.
+  virtual void Start(Mode mode);
+
+  // Schedules the configuration task specified by |params|. Returns true if
+  // the configuration task executed immediately, false if it had to be
+  // scheduled for a later attempt. |params.ready_task| is invoked whenever the
+  // configuration task executes.
+  // Note: must already be in CONFIGURATION mode.
+  virtual bool ScheduleConfiguration(const ConfigurationParams& params);
 
   // Request that any running syncer task stop as soon as possible and
   // cancel all scheduled tasks. This function can be called from any thread,
@@ -79,21 +110,13 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
   // The meat and potatoes. Both of these methods will post a delayed task
   // to attempt the actual nudge (see ScheduleNudgeImpl).
   void ScheduleNudgeAsync(const base::TimeDelta& delay, NudgeSource source,
-                     syncer::ModelTypeSet types,
-                     const tracked_objects::Location& nudge_location);
+                          syncer::ModelTypeSet types,
+                          const tracked_objects::Location& nudge_location);
   void ScheduleNudgeWithPayloadsAsync(
       const base::TimeDelta& delay, NudgeSource source,
       const syncer::ModelTypePayloadMap& types_with_payloads,
       const tracked_objects::Location& nudge_location);
 
-  // Schedule a configuration cycle. May execute immediately or at a later time
-  // (depending on backoff/throttle state).
-  // Note: The source argument of this function must come from the subset of
-  // GetUpdatesCallerInfo values related to configurations.
-  void ScheduleConfiguration(
-      syncer::ModelTypeSet types,
-      sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source);
-
   void CleanupDisabledTypes();
 
   // Change status of notifications in the SyncSessionContext.
@@ -158,6 +181,7 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
     SyncSessionJob();
     SyncSessionJob(SyncSessionJobPurpose purpose, base::TimeTicks start,
         linked_ptr<sessions::SyncSession> session, bool is_canary_job,
+        const ConfigurationParams& config_params,
         const tracked_objects::Location& nudge_location);
     ~SyncSessionJob();
     static const char* GetPurposeString(SyncSessionJobPurpose purpose);
@@ -166,6 +190,7 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
     base::TimeTicks scheduled_start;
     linked_ptr<sessions::SyncSession> session;
     bool is_canary_job;
+    ConfigurationParams config_params;
 
     // This is the location the job came from.  Used for debugging.
     // In case of multiple nudges getting coalesced this stores the