[Sync] ModelTypeWorker should delete tracker for entity deleted on the server

components/sync/engine_impl/worker_entity_tracker.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync/engine_impl/worker_entity_tracker.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/base/time.h"
 #include "components/sync/syncable/syncable_util.h"
 
 namespace syncer {
 
 WorkerEntityTracker::WorkerEntityTracker(const std::string& client_tag_hash)
     : client_tag_hash_(client_tag_hash) {
   DCHECK(!client_tag_hash_.empty());
 }
 
 WorkerEntityTracker::~WorkerEntityTracker() {}
 
 bool WorkerEntityTracker::HasPendingCommit() const {
   return !!pending_commit_;
 }
 
+bool WorkerEntityTracker::PendingCommitIsDeletion() const {
+  DCHECK(pending_commit_);
+  return pending_commit_->entity.value().is_deleted();
+}
+
 void WorkerEntityTracker::PopulateCommitProto(
     sync_pb::SyncEntity* commit_entity) const {
   DCHECK(HasPendingCommit());
 
   const EntityData& entity = pending_commit_->entity.value();
   DCHECK_EQ(client_tag_hash_, entity.client_tag_hash);
 
   commit_entity->set_id_string(id_);
   commit_entity->set_client_defined_unique_tag(client_tag_hash_);
   commit_entity->set_version(base_version_);
@@ skipping 160 matching lines @@
 bool WorkerEntityTracker::IsServerKnown() const {
   return base_version_ != kUncommittedVersion;
 }
 
 void WorkerEntityTracker::ClearPendingCommit() {
   pending_commit_.reset();
   pending_commit_specifics_hash_.clear();
 }
 
 }  // namespace syncer