[Sync] Remove unneeded 'using syncer::' lines and 'syncer::' scopings

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 0ca2f5db5a14be3d236213750e9489eda6a919f6..b0a8fcf21ade80b5ed14cc909972bac2c3b1c329 100644
--- a/sync/engine/sync_scheduler.h
+++ b/sync/engine/sync_scheduler.h
@@ -44,8 +44,8 @@ struct ConfigurationParams {
   ConfigurationParams();
   ConfigurationParams(
       const sync_pb::GetUpdatesCallerInfo::GetUpdatesSource& source,
-      const syncer::ModelTypeSet& types_to_download,
-      const syncer::ModelSafeRoutingInfo& routing_info,
+      const ModelTypeSet& types_to_download,
+      const ModelSafeRoutingInfo& routing_info,
       KeystoreKeyStatus keystore_key_status,
       const base::Closure& ready_task);
   ~ConfigurationParams();
@@ -53,7 +53,7 @@ struct ConfigurationParams {
   // Source for the configuration.
   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source;
   // The types that should be downloaded.
-  syncer::ModelTypeSet types_to_download;
+  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.
@@ -109,11 +109,11 @@ 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,
+                          ModelTypeSet types,
                           const tracked_objects::Location& nudge_location);
   void ScheduleNudgeWithPayloadsAsync(
       const base::TimeDelta& delay, NudgeSource source,
-      const syncer::ModelTypePayloadMap& types_with_payloads,
+      const ModelTypePayloadMap& types_with_payloads,
       const tracked_objects::Location& nudge_location);
 
   void CleanupDisabledTypes();
@@ -331,7 +331,7 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
   void ScheduleNudgeImpl(
       const base::TimeDelta& delay,
       sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source,
-      const syncer::ModelTypePayloadMap& types_with_payloads,
+      const ModelTypePayloadMap& types_with_payloads,
       bool is_canary_job, const tracked_objects::Location& nudge_location);
 
   // Returns true if the client is currently in exponential backoff.
@@ -353,8 +353,8 @@ class SyncScheduler : public sessions::SyncSession::Delegate {
   void OnServerConnectionErrorFixed();
 
   // The pointer is owned by the caller.
-  syncer::sessions::SyncSession* CreateSyncSession(
-      const syncer::sessions::SyncSourceInfo& info);
+  sessions::SyncSession* CreateSyncSession(
+      const sessions::SyncSourceInfo& info);
 
   // Creates a session for a poll and performs the sync.
   void PollTimerCallback();