sync: add WIFI_CREDENTIALS protobuf, ModelType, and preference

sync/protocol/proto_enum_conversions.cc

Index: sync/protocol/proto_enum_conversions.cc
diff --git a/sync/protocol/proto_enum_conversions.cc b/sync/protocol/proto_enum_conversions.cc
index 4c439833550b98246135ee2732470b65678ecc3f..eff952fe0f5c4b9998a26daa709b43131cae7dee 100644
--- a/sync/protocol/proto_enum_conversions.cc
+++ b/sync/protocol/proto_enum_conversions.cc
@@ -80,6 +80,19 @@ const char* GetPageTransitionRedirectTypeString(
   return "";
 }
 
+const char* GetWifiCredentialSecurityClassString(
+    sync_pb::WifiCredentialSpecifics::SecurityClass security_class) {
+  ASSERT_ENUM_BOUNDS(sync_pb::WifiCredentialSpecifics, SecurityClass,
+                     SECURITY_CLASS_INVALID, SECURITY_CLASS_PSK);
+  switch (security_class) {
+    ENUM_CASE(sync_pb::WifiCredentialSpecifics, SECURITY_CLASS_INVALID);
+    ENUM_CASE(sync_pb::WifiCredentialSpecifics, SECURITY_CLASS_NONE);
+    ENUM_CASE(sync_pb::WifiCredentialSpecifics, SECURITY_CLASS_WEP);
+    ENUM_CASE(sync_pb::WifiCredentialSpecifics, SECURITY_CLASS_PSK);
+  }
+  NOTREACHED();
+  return "";
+}
 const char* GetUpdatesSourceString(
     sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source) {
   ASSERT_ENUM_BOUNDS(sync_pb::GetUpdatesCallerInfo, GetUpdatesSource,