[Sync] Stop updating local device info time stamp on merge.

components/sync/device_info/device_info_sync_bridge_unittest.cc

Index: components/sync/device_info/device_info_sync_bridge_unittest.cc
diff --git a/components/sync/device_info/device_info_sync_bridge_unittest.cc b/components/sync/device_info/device_info_sync_bridge_unittest.cc
index 115166664dbf96858d9130d5ce7a49276e8554ec..583553a2ad252938c87ceeef9ee59372b6b4f99b 100644
--- a/components/sync/device_info/device_info_sync_bridge_unittest.cc
+++ b/components/sync/device_info/device_info_sync_bridge_unittest.cc
@@ -663,6 +663,21 @@ TEST_F(DeviceInfoSyncBridgeTest, MergeLocalGuid) {
   EXPECT_TRUE(processor()->put_multimap().empty());
 }
 
+TEST_F(DeviceInfoSyncBridgeTest, MergeLocalGuidBeforeReconcile) {
+  InitializeBridge();
+  const DeviceInfoSpecifics specifics = CreateSpecifics(kDefaultLocalSuffix);
+
+  // The message loop is never pumped, which means local data/metadata is never
+  // loaded, and thus reconcile is never called. The bridge should ignore this
+  // EntityData because its cache guid is the same the local device's.
+  const SyncError error = bridge()->MergeSyncData(
+      bridge()->CreateMetadataChangeList(),
+      {{specifics.cache_guid(), SpecificsToEntity(specifics)}});
+  EXPECT_FALSE(error.IsSet());
+  EXPECT_EQ(0, change_count());
+  EXPECT_EQ(0u, bridge()->GetAllDeviceInfo().size());
+}
+
 TEST_F(DeviceInfoSyncBridgeTest, CountActiveDevices) {
   InitializeAndPump();
   EXPECT_EQ(1, bridge()->CountActiveDevices());