Convert //sync from scoped_ptr to std::unique_ptr

sync/engine/worker_entity_tracker_unittest.cc

Index: sync/engine/worker_entity_tracker_unittest.cc
diff --git a/sync/engine/worker_entity_tracker_unittest.cc b/sync/engine/worker_entity_tracker_unittest.cc
index 871b82f45b39f51acabd05ef5b61bb6348be5f90..93f7f4482fd53ce6d2b065d59ccc9ae353b0db0d 100644
--- a/sync/engine/worker_entity_tracker_unittest.cc
+++ b/sync/engine/worker_entity_tracker_unittest.cc
@@ -7,7 +7,8 @@
 
 #include <stdint.h>
 
-#include "base/memory/scoped_ptr.h"
+#include <memory>
+
 #include "base/time/time.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/non_blocking_sync_common.h"
@@ -76,7 +77,7 @@ class WorkerEntityTrackerTest : public ::testing::Test {
   const base::Time kCtime;
   const base::Time kMtime;
   sync_pb::EntitySpecifics specifics;
-  scoped_ptr<WorkerEntityTracker> entity_;
+  std::unique_ptr<WorkerEntityTracker> entity_;
 };
 
 // Construct a new entity from a server update.  Then receive another update.