7 files changed, 86 insertions, 0 deletions
diff --git a/sync/internal_api/DEPS b/sync/internal_api/DEPS
index 13e6b8a..42ab18e 100644
--- a/sync/internal_api/DEPS
+++ b/sync/internal_api/DEPS
@@ -4,6 +4,7 @@ include_rules = [
   "+net/http",
   "+net/test",
   "+net/url_request",
+  "+sql",
   "+sync/base",
   "+sync/engine",
   "+sync/js",
diff --git a/sync/internal_api/public/util/sync_db_util.h b/sync/internal_api/public/util/sync_db_util.h
new file mode 100644
index 0000000..3784a10
--- /dev/null
+++ b/sync/internal_api/public/util/sync_db_util.h
@@ -0,0 +1,30 @@
+// 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.
+
+#ifndef SYNC_INTERNAL_API_PUBLIC_UTIL_SYNC_DB_UTIL_H_
+#define SYNC_INTERNAL_API_PUBLIC_UTIL_SYNC_DB_UTIL_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/time/time.h"
+#include "sync/base/sync_export.h"
+
+namespace base {
+class FilePath;
+class SingleThreadTaskRunner;
+}  // namespace base
+
+namespace syncer {
+
+// Check integrity of sync DB under |sync_dir|. Invoke |callback| with last
+// modified time if integrity check passes, with NULL time otherwise. This
+// is called on either sync thread or IO thread.
+SYNC_EXPORT void CheckSyncDbLastModifiedTime(
+    const base::FilePath& sync_dir,
+    scoped_refptr<base::SingleThreadTaskRunner> callback_runner,
+    base::Callback<void(base::Time)> callback);
+
+}  // namesapce syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_UTIL_SYNC_DB_UTIL_H_
diff --git a/sync/internal_api/sync_db_util.cc b/sync/internal_api/sync_db_util.cc
new file mode 100644
index 0000000..c12889d
--- /dev/null
+++ b/sync/internal_api/sync_db_util.cc
@@ -0,0 +1,38 @@
+// 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 "sync/internal_api/public/util/sync_db_util.h"
+
+#include "base/files/file_path.h"
+#include "base/single_thread_task_runner.h"
+#include "sql/connection.h"
+#include "sync/syncable/directory.h"
+
+namespace syncer {
+
+void CheckSyncDbLastModifiedTime(
+    const base::FilePath& sync_dir,
+    scoped_refptr<base::SingleThreadTaskRunner> callback_runner,
+    base::Callback<void(base::Time)> callback) {
+  const base::FilePath sync_db =
+      sync_dir.Append(syncable::Directory::kSyncDatabaseFilename);
+
+  base::File f(sync_db, base::File::FLAG_OPEN | base::File::FLAG_READ);
+  base::File::Info info;
+  if (!f.IsValid() || !f.GetInfo(&info)) {
+    callback_runner->PostTask(FROM_HERE, base::Bind(callback, base::Time()));
+    return;
+  }
+  f.Close();
+
+  sql::Connection db;
+  if (!db.Open(sync_db) || !db.QuickIntegrityCheck()) {
+    callback_runner->PostTask(FROM_HERE, base::Bind(callback, base::Time()));
+  } else {
+    callback_runner->PostTask(FROM_HERE,
+                              base::Bind(callback, info.last_modified));
+  }
+}
+
+}  // namespace syncer
diff --git a/sync/protocol/DEPS b/sync/protocol/DEPS
index f8f9de5..d623db8 100644
--- a/sync/protocol/DEPS
+++ b/sync/protocol/DEPS
@@ -1,4 +1,5 @@
 include_rules = [
   "+sync/base",
   "+sync/internal_api/public/base",
+  "+sync/util",
 ]
diff --git a/sync/protocol/device_info_specifics.proto b/sync/protocol/device_info_specifics.proto
index 67eb469..f87b361 100644
--- a/sync/protocol/device_info_specifics.proto
+++ b/sync/protocol/device_info_specifics.proto
@@ -34,4 +34,8 @@ message DeviceInfoSpecifics {
 
   // The Chrome instance's version.  Updated (if necessary) on every startup.
   optional string chrome_version = 5;
+
+  // Last time when pre-sync data on the device was saved. The device can be
+  // restored to state back to this time. In millisecond since UNIX epoch.
+  optional int64 backup_timestamp = 6;
 }
diff --git a/sync/protocol/proto_value_conversions.cc b/sync/protocol/proto_value_conversions.cc
index 8e58af4..2716210 100644
--- a/sync/protocol/proto_value_conversions.cc
+++ b/sync/protocol/proto_value_conversions.cc
@@ -10,8 +10,10 @@
 
 #include "base/base64.h"
 #include "base/basictypes.h"
+#include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/time/time.h"
 #include "base/values.h"
 #include "sync/internal_api/public/base/unique_position.h"
 #include "sync/protocol/app_list_specifics.pb.h"
@@ -41,6 +43,7 @@
 #include "sync/protocol/theme_specifics.pb.h"
 #include "sync/protocol/typed_url_specifics.pb.h"
 #include "sync/protocol/unique_position.pb.h"
+#include "sync/util/time.h"
 
 namespace syncer {
 
@@ -82,6 +85,11 @@ base::ListValue* MakeRepeatedValue(const F& fields, V* (*converter_fn)(T)) {
   return list;
 }
 
+base::StringValue* MakeTimestampValue(int64 tm) {
+  return new base::StringValue(
+      base::TimeFormatShortDateAndTime(syncer::ProtoTimeToTime(tm)));
+}
+
 }  // namespace
 
 // Helper macros to reduce the amount of boilerplate.
@@ -102,6 +110,7 @@ base::ListValue* MakeRepeatedValue(const F& fields, V* (*converter_fn)(T)) {
 #define SET_INT64(field) SET(field, MakeInt64Value)
 #define SET_INT64_REP(field) SET_REP(field, MakeInt64Value)
 #define SET_STR(field) SET(field, new base::StringValue)
+#define SET_TIME_STR(field) SET(field, MakeTimestampValue)
 #define SET_STR_REP(field) \
   value->Set(#field, \
              MakeRepeatedValue<const std::string&, \
@@ -489,6 +498,7 @@ base::DictionaryValue* DeviceInfoSpecificsToValue(
   SET_ENUM(device_type, GetDeviceTypeString);
   SET_STR(sync_user_agent);
   SET_STR(chrome_version);
+  SET_TIME_STR(backup_timestamp);
   return value;
 }
 
diff --git a/sync/sync_internal_api.gypi b/sync/sync_internal_api.gypi
index 1ff913f..7d92f68 100644
--- a/sync/sync_internal_api.gypi
+++ b/sync/sync_internal_api.gypi
@@ -135,6 +135,7 @@
     'internal_api/public/util/report_unrecoverable_error_function.h',
     'internal_api/public/util/sync_string_conversions.cc',
     'internal_api/public/util/sync_string_conversions.h',
+    'internal_api/public/util/sync_db_util.h',
     'internal_api/public/util/syncer_error.cc',
     'internal_api/public/util/syncer_error.h',
     'internal_api/public/util/unrecoverable_error_handler.h',
@@ -152,6 +153,7 @@
     'internal_api/sync_context_proxy.cc',
     'internal_api/sync_context_proxy_impl.cc',
     'internal_api/sync_context_proxy_impl.h',
+    'internal_api/sync_db_util.cc',
     'internal_api/sync_encryption_handler_impl.cc',
     'internal_api/sync_encryption_handler_impl.h',
     'internal_api/sync_manager_factory.cc',