[USS] Show USS counters in about:sync page

components/sync/core/shared_model_type_processor.h

Index: components/sync/core/shared_model_type_processor.h
diff --git a/components/sync/core/shared_model_type_processor.h b/components/sync/core/shared_model_type_processor.h
index 4be1558bcfaf07f1b3f3c937916449c769017945..a01220f672aba150d7529d886d5e60efe9b5ecd5 100644
--- a/components/sync/core/shared_model_type_processor.h
+++ b/components/sync/core/shared_model_type_processor.h
@@ -22,6 +22,7 @@
 #include "components/sync/base/model_type.h"
 #include "components/sync/core/model_type_processor.h"
 #include "components/sync/core/non_blocking_sync_common.h"
+#include "components/sync/engine/cycle/status_counters.h"
 #include "components/sync/protocol/data_type_state.pb.h"
 #include "components/sync/protocol/sync.pb.h"
 
@@ -60,6 +61,13 @@ class SharedModelTypeProcessor : public ModelTypeProcessor,
       const base::Callback<void(const syncer::ModelType type,
                                 std::unique_ptr<base::ListValue>)>& callback);
 
+  // Returns StatusCounters for data type to |callback|.
+  // Used for updating data type counters in chrome://sync-internals.
+  void GetStatusCounters(
+      const scoped_refptr<base::TaskRunner>& task_runner,
+      const base::Callback<void(syncer::ModelType,
+                                const syncer::StatusCounters&)>& callback);
+
   // ModelTypeChangeProcessor implementation.
   void Put(const std::string& storage_key,
            std::unique_ptr<EntityData> entity_data,