Sync: Avoid 3 passes over SyncDarta DB when loading the directory from the disk

sync/test/test_directory_backing_store.h

 // Copyright (c) 2012 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.
 
 #ifndef SYNC_TEST_TEST_DIRECTORY_BACKING_STORE_H_
 #define SYNC_TEST_TEST_DIRECTORY_BACKING_STORE_H_
 
 #include "base/gtest_prod_util.h"
 #include "sync/syncable/directory_backing_store.h"
 
 namespace syncer {
 namespace syncable {
 
 // This implementation of DirectoryBackingStore does not manage its own
 // database.  This makes it more flexible (and more complex) than the
 // InMemoryDirectoryBackingStore.
 class TestDirectoryBackingStore : public DirectoryBackingStore {
  public:
   // This constructor takes a handle to a database.  The caller maintains
   // ownership of this handle.
   //
   // This is very brittle.  You should not be using this class or this
   // constructor unless you understand and intend to test the
   // DirectoryBackingStore's internals.
   TestDirectoryBackingStore(const std::string& dir_name,
                             sql::Connection* connection);
   ~TestDirectoryBackingStore() override;
   DirOpenResult Load(Directory::MetahandlesMap* handles_map,
                      JournalIndex* delete_journals,
+                     MetahandleSet* metahandles_to_purge,
                      Directory::KernelLoadInfo* kernel_load_info) override;
-
+  bool DeleteEntries(const MetahandleSet& handles);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion67To68);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion68To69);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion69To70);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion70To71);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion71To72);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion72To73);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion73To74);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion74To75);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion75To76);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateVersion76To77);
@@ skipping 16 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, GenerateCacheGUID);
   FRIEND_TEST_ALL_PREFIXES(MigrationTest, ToCurrentVersion);
   FRIEND_TEST_ALL_PREFIXES(DirectoryBackingStoreTest, MigrateToLatestAndDump);
   friend class MigrationTest;
 };
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif  // SYNC_TEST_TEST_DIRECTORY_BACKING_STORE_H_