Revert of Let SyncBackupManager keep backup data in memory until shutdown. Only persist

sync/syncable/deferred_on_disk_directory_backing_store.cc

Index: sync/syncable/deferred_on_disk_directory_backing_store.cc
diff --git a/sync/syncable/deferred_on_disk_directory_backing_store.cc b/sync/syncable/deferred_on_disk_directory_backing_store.cc
deleted file mode 100644
index 04540803f1bd199bf4ef77a2c3f6b0a0ea14d45c..0000000000000000000000000000000000000000
--- a/sync/syncable/deferred_on_disk_directory_backing_store.cc
+++ /dev/null
@@ -1,73 +0,0 @@
-// Copyright (c) 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 "sync/syncable/deferred_on_disk_directory_backing_store.h"
-
-#include "base/logging.h"
-#include "base/metrics/histogram.h"
-#include "base/stl_util.h"
-#include "sync/syncable/syncable-inl.h"
-
-namespace syncer {
-namespace syncable {
-
-DeferredOnDiskDirectoryBackingStore::DeferredOnDiskDirectoryBackingStore(
-    const std::string& dir_name, const base::FilePath& backing_filepath)
-    : DirectoryBackingStore(dir_name),
-      backing_filepath_(backing_filepath),
-      db_is_on_disk_(false) {
-}
-
-DeferredOnDiskDirectoryBackingStore::~DeferredOnDiskDirectoryBackingStore() {}
-
-bool DeferredOnDiskDirectoryBackingStore::SaveChanges(
-    const Directory::SaveChangesSnapshot& snapshot) {
-  DCHECK(CalledOnValidThread());
-
-  // Back out early if there is nothing to save.
-  if (snapshot.dirty_metas.empty() && snapshot.metahandles_to_purge.empty() &&
-      snapshot.delete_journals.empty() &&
-      snapshot.delete_journals_to_purge.empty()) {
-    return true;
-  }
-
-  if (!db_is_on_disk_) {
-    if (!base::DeleteFile(backing_filepath_, false))
-      return false;
-
-    // Reopen DB on disk.
-    db_.reset(new sql::Connection);
-    db_->set_exclusive_locking();
-    db_->set_page_size(4096);
-    if (!db_->Open(backing_filepath_) || !InitializeTables())
-      return false;
-
-    db_is_on_disk_ = true;
-  }
-
-  return DirectoryBackingStore::SaveChanges(snapshot);
-}
-
-DirOpenResult DeferredOnDiskDirectoryBackingStore::Load(
-    Directory::MetahandlesMap* handles_map,
-    JournalIndex* delete_journals,
-    Directory::KernelLoadInfo* kernel_load_info) {
-  // Open an in-memory database at first to create initial sync data needed by
-  // Directory.
-  CHECK(!db_->is_open());
-  if (!db_->OpenInMemory())
-    return FAILED_OPEN_DATABASE;
-
-  if (!InitializeTables())
-    return FAILED_OPEN_DATABASE;
-  if (!LoadEntries(handles_map))
-    return FAILED_DATABASE_CORRUPT;
-  if (!LoadInfo(kernel_load_info))
-    return FAILED_DATABASE_CORRUPT;
-
-  return OPENED;
-}
-
-}  // namespace syncable
-}  // namespace syncer