[Sync] USS: Filter out tombstones for initial sync.

components/sync/engine_impl/uss_migrator_unittest.cc

 // Copyright 2016 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/uss_migrator.h"
 
 #include <memory>
 #include <string>
 #include <utility>
 
@@ skipping 63 matching lines @@
     directory()->SetDownloadProgress(kModelType, progress_marker);
   }
 
   void CreateTypeRoot() { entry_factory_->CreateTypeRootNode(kModelType); }
 
   int64_t InsertEntity(const std::string& key, const std::string& value) {
     const sync_pb::EntitySpecifics specifics = GenerateSpecifics(key, value);
     return entry_factory_->CreateSyncedItem(key, kModelType, false, specifics);
   }
 
+  int64_t DeleteEntity(const std::string& key) {
+    return entry_factory_->CreateTombstone(key, kModelType);
+  }
+
   base::Time GetCtimeForEntity(int64_t metahandle) {
     ReadTransaction trans(FROM_HERE, user_share());
     ReadNode read_node(&trans);
     auto result = read_node.InitByIdLookup(metahandle);
     DCHECK_EQ(BaseNode::INIT_OK, result);
     return read_node.GetEntry()->GetServerCtime();
   }
 
   UserShare* user_share() { return test_user_share_.user_share(); }
   MockNudgeHandler* nudge_handler() { return &nudge_handler_; }
@@ skipping 74 matching lines @@
 
   EXPECT_EQ(1U, processor()->GetNumUpdateResponses());
   EXPECT_EQ(3U, processor()->GetNthUpdateResponse(0).size());
 
   UpdateResponseDataList updates = processor()->GetNthUpdateResponse(0);
   EXPECT_EQ(kTag1, updates.at(0).entity.value().specifics.preference().name());
   EXPECT_EQ(kTag2, updates.at(1).entity.value().specifics.preference().name());
   EXPECT_EQ(kTag3, updates.at(2).entity.value().specifics.preference().name());
 }
 
+TEST_F(UssMigratorTest, MigrateIgnoresTombstone) {
+  CreateTypeRoot();
+  SetProgressMarkerToken(kToken1);
+  DeleteEntity(kTag1);
+
+  ASSERT_TRUE(MigrateDirectoryData(kModelType, user_share(), worker()));
+
+  EXPECT_EQ(0, nudge_handler()->GetNumInitialDownloadNudges());
+  EXPECT_EQ(1U, processor()->GetNumUpdateResponses());
+  EXPECT_EQ(0U, processor()->GetNthUpdateResponse(0).size());
+}
+
 TEST_F(UssMigratorTest, MigrateZero) {
   CreateTypeRoot();
   SetProgressMarkerToken(kToken1);
 
   ASSERT_TRUE(MigrateDirectoryData(kModelType, user_share(), worker()));
 
   EXPECT_EQ(0, nudge_handler()->GetNumInitialDownloadNudges());
   EXPECT_EQ(1U, processor()->GetNumUpdateResponses());
   EXPECT_EQ(0U, processor()->GetNthUpdateResponse(0).size());
 }
 
 TEST_F(UssMigratorTest, MissingTypeRoot) {
   EXPECT_EQ(0, nudge_handler()->GetNumInitialDownloadNudges());
   ASSERT_FALSE(MigrateDirectoryData(kModelType, user_share(), worker()));
   EXPECT_EQ(1, nudge_handler()->GetNumInitialDownloadNudges());
   EXPECT_EQ(0U, processor()->GetNumUpdateResponses());
 }
 
 }  // namespace syncer