[Sync] Move sessions/ to engine/cycle/ and rename things to match.

components/sync/engine_impl/cycle/data_type_tracker.cc

Index: components/sync/engine_impl/cycle/data_type_tracker.cc
diff --git a/components/sync/sessions_impl/data_type_tracker.cc b/components/sync/engine_impl/cycle/data_type_tracker.cc
similarity index 98%
rename from components/sync/sessions_impl/data_type_tracker.cc
rename to components/sync/engine_impl/cycle/data_type_tracker.cc
index bdd3488e185ab7d6e71ce89d9287ff5b71c516f6..7040d4fe5baf5b152b77a44fb33833c73f83b87e 100644
--- a/components/sync/sessions_impl/data_type_tracker.cc
+++ b/components/sync/engine_impl/cycle/data_type_tracker.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/sync/sessions_impl/data_type_tracker.h"
+#include "components/sync/engine_impl/cycle/data_type_tracker.h"
 
 #include <stddef.h>
 
@@ -10,10 +10,9 @@
 
 #include "base/logging.h"
 #include "components/sync/base/invalidation_interface.h"
-#include "components/sync/sessions_impl/nudge_tracker.h"
+#include "components/sync/engine_impl/cycle/nudge_tracker.h"
 
 namespace syncer {
-namespace sessions {
 
 DataTypeTracker::DataTypeTracker()
     : local_nudge_count_(0),
@@ -235,5 +234,4 @@ void DataTypeTracker::UpdateLocalNudgeDelay(base::TimeDelta delay) {
   nudge_delay_ = delay;
 }
 
-}  // namespace sessions
 }  // namespace syncer