[USS] Show USS counters in about:sync page

components/sync/core/shared_model_type_processor.cc

Index: components/sync/core/shared_model_type_processor.cc
diff --git a/components/sync/core/shared_model_type_processor.cc b/components/sync/core/shared_model_type_processor.cc
index 85475769c889196ab6e59c3caa382d54b8758dd9..82b0a36618f09b7e9330f95b79456c84346b4e39 100644
--- a/components/sync/core/shared_model_type_processor.cc
+++ b/components/sync/core/shared_model_type_processor.cc
@@ -202,6 +202,21 @@ void SharedModelTypeProcessor::GetAllNodes(
                  base::Unretained(this), task_runner, callback));
 }
 
+void SharedModelTypeProcessor::GetStatusCounters(
+    const scoped_refptr<base::TaskRunner>& task_runner,
+    const base::Callback<void(syncer::ModelType,
+                              const syncer::StatusCounters&)>& callback) {
+  DCHECK(CalledOnValidThread());
+  syncer::StatusCounters counters;
+  for (auto it = entities_.begin(); it != entities_.end(); ++it) {
+    ++counters.num_entries_and_tombstones;

[pavely, 2016/10/03 21:40:14]

Please move num_entries_and_tombstones calculation outside the loop and change
it to "counters.num_entries_and_tombstones = entities_.size();"

[Gang Wu, 2016/10/06 00:20:22]

Done.

+    if (!it->second->metadata().is_deleted()) {
+      ++counters.num_entries;
+    }
+  }
+  task_runner->PostTask(FROM_HERE, base::Bind(callback, type_, counters));
+}
+
 void SharedModelTypeProcessor::DisableSync() {
   DCHECK(CalledOnValidThread());
   std::unique_ptr<MetadataChangeList> change_list =