[Sync] On disabling sync, device info records are removed.

components/sync/device_info/device_info_service.cc

 // Copyright 2015 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/device_info/device_info_service.h"
 
 #include <algorithm>
 #include <set>
 #include <utility>
 
@@ skipping 162 matching lines @@
 std::string DeviceInfoService::GetClientTag(const EntityData& entity_data) {
   DCHECK(entity_data.specifics.has_device_info());
   return DeviceInfoUtil::SpecificsToTag(entity_data.specifics.device_info());
 }
 
 std::string DeviceInfoService::GetStorageKey(const EntityData& entity_data) {
   DCHECK(entity_data.specifics.has_device_info());
   return entity_data.specifics.device_info().cache_guid();
 }
 
+void DeviceInfoService::DisableSync() {
+  // TODO(skym, crbug.com/659263): Would it be reasonable to pulse_timer_.Stop()
+  // or subscription_.reset() here?
+
+  // Allow deletion of metadata to happen before the deletion of data below. If
+  // we crash after removing metadata but not regular data, then merge can
+  // handle pairing everything back up.
+  ModelTypeService::DisableSync();
+
+  // Remove all local data, if sync is being disabled, the user has expressed
+  // their desire to not have knowledge about other devices.
+  if (!all_data_.empty()) {
+    std::unique_ptr<WriteBatch> batch = store_->CreateWriteBatch();
+    for (const auto& kv : all_data_) {
+      store_->DeleteData(batch.get(), kv.first);
+    }
+    store_->CommitWriteBatch(
+        std::move(batch),
+        base::Bind(&DeviceInfoService::OnCommit, base::AsWeakPtr(this)));
+
+    all_data_.clear();
+    NotifyObservers();
+  }
+}
+
 bool DeviceInfoService::IsSyncing() const {
   return !all_data_.empty();
 }
 
 std::unique_ptr<DeviceInfo> DeviceInfoService::GetDeviceInfo(
     const std::string& client_id) const {
   const ClientIdToSpecifics::const_iterator iter = all_data_.find(client_id);
   if (iter == all_data_.end()) {
     return std::unique_ptr<DeviceInfo>();
   }
@@ skipping 278 matching lines @@
 Time DeviceInfoService::GetLastUpdateTime(
     const DeviceInfoSpecifics& specifics) {
   if (specifics.has_last_updated_timestamp()) {
     return ProtoTimeToTime(specifics.last_updated_timestamp());
   } else {
     return Time();
   }
 }
 
 }  // namespace syncer