[Sync] Add tests for invalid specifics field number handling

sync/engine/store_timestamps_command.cc

Index: sync/engine/store_timestamps_command.cc
diff --git a/sync/engine/store_timestamps_command.cc b/sync/engine/store_timestamps_command.cc
index 6f381b0d7a36510fdb1f0e64a658c5d001f47422..cbff68fec50df8a8344d596ae2cdadc4706a620c 100644
--- a/sync/engine/store_timestamps_command.cc
+++ b/sync/engine/store_timestamps_command.cc
@@ -4,39 +4,44 @@
 
 #include "sync/engine/store_timestamps_command.h"
 
-#include "sync/internal_api/public/base/model_type.h"
+#include "base/logging.h"
 #include "sync/sessions/status_controller.h"
 #include "sync/sessions/sync_session.h"
 #include "sync/syncable/directory.h"
 
 namespace syncer {
 
+ModelTypeSet ProcessNewProgressMarkers(
+    const sync_pb::GetUpdatesResponse& response,
+    syncable::Directory* dir) {
+  ModelTypeSet forward_progress_types;
+  // If a marker was omitted for any one type, that indicates no
+  // change from the previous state.
+  for (int i = 0; i < response.new_progress_marker_size(); ++i) {
+    int field_number = response.new_progress_marker(i).data_type_id();
+    ModelType model_type = GetModelTypeFromSpecificsFieldNumber(field_number);
+    if (!IsRealDataType(model_type)) {
+      DLOG(WARNING) << "Unknown field number " << field_number;
+      continue;
+    }
+    forward_progress_types.Put(model_type);
+    dir->SetDownloadProgress(model_type, response.new_progress_marker(i));
+  }
+  return forward_progress_types;
+}
+
 StoreTimestampsCommand::StoreTimestampsCommand() {}
 StoreTimestampsCommand::~StoreTimestampsCommand() {}
 
 SyncerError StoreTimestampsCommand::ExecuteImpl(
     sessions::SyncSession* session) {
-  syncable::Directory* dir = session->context()->directory();
-
   const sync_pb::GetUpdatesResponse& updates =
       session->status_controller().updates_response().get_updates();
 
   sessions::StatusController* status = session->mutable_status_controller();
 
-  // Update the progress marker tokens from the server result.  If a marker
-  // was omitted for any one type, that indicates no change from the previous
-  // state.
-  ModelTypeSet forward_progress_types;
-  for (int i = 0; i < updates.new_progress_marker_size(); ++i) {
-    int field_number = updates.new_progress_marker(i).data_type_id();
-    ModelType model_type = GetModelTypeFromSpecificsFieldNumber(field_number);
-    if (!IsRealDataType(model_type)) {
-      NOTREACHED() << "Unknown field number " << field_number;
-      continue;
-    }
-    forward_progress_types.Put(model_type);
-    dir->SetDownloadProgress(model_type, updates.new_progress_marker(i));
-  }
+  ModelTypeSet forward_progress_types =
+      ProcessNewProgressMarkers(updates, session->context()->directory());
   DCHECK(!forward_progress_types.Empty() ||
          updates.changes_remaining() == 0);
   if (VLOG_IS_ON(1)) {