[Sync] Implementation of model association for passwords using sync API

sync/api/sync_error.cc

Index: sync/api/sync_error.cc
diff --git a/sync/api/sync_error.cc b/sync/api/sync_error.cc
index ee6885cb229285f479b8bc57284dda35d5068bb2..9dc4ef67bcd8cea64ea6ebfcc82445b601d16dad 100644
--- a/sync/api/sync_error.cc
+++ b/sync/api/sync_error.cc
@@ -8,6 +8,7 @@
 
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "sync/internal_api/public/base/model_type.h"
 
 namespace syncer {
@@ -137,4 +138,10 @@ void PrintTo(const SyncError& sync_error, std::ostream* os) {
   *os << sync_error.ToString();
 }
 
+void SyncError::LogDataLoadFailure(ModelType model_type) {
+  UMA_HISTOGRAM_ENUMERATION("Sync.LocalDataFailedToLoad",
+                            model_type,
+                            MODEL_TYPE_COUNT);
+}
+
 }  // namespace syncer