Enable SyncUSSNigori by default

This CL enables SyncUSSNigori by default, because it should be launched
soon and removes one Directory-specific test, which is not relevant
once USS implementation is enabled for all datatypes.

Bug: 922900
Change-Id: I0f6c71a4a1a6a06a3fed510e11d28b770972c6c6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2074700
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745034}

components/sync/driver/glue/sync_engine_impl_unittest.cc

@@ -691,19 +691,6 @@ TEST_F(SyncEngineImplTest, DownloadControlTypesRestart) {
             fake_manager_->GetAndResetConfigureReason());
 }
 
-TEST_F(SyncEngineImplTest, TestStartupWithOldSyncData) {
-  const char* nonsense = "slon";
-  base::FilePath temp_directory =
-      temp_dir_.GetPath().Append(base::FilePath(kTestSyncDir));
-  base::FilePath sync_file = temp_directory.AppendASCII("SyncData.sqlite3");
-  ASSERT_TRUE(base::CreateDirectory(temp_directory));
-  ASSERT_NE(-1, base::WriteFile(sync_file, nonsense, strlen(nonsense)));
-
-  InitializeBackend(true);
-
-  EXPECT_FALSE(base::PathExists(sync_file));
-}
-
 // If bookmarks encounter an error that results in disabling without purging
 // (such as when the type is unready), and then is explicitly disabled, the
 // SyncEngine needs to tell the manager to purge the type, even though

components/sync/driver/sync_driver_switches.cc

@@ -59,7 +59,7 @@ const base::Feature kSyncUSSPasswords{"SyncUSSPasswords",
 
 // Enable USS implementation of Nigori datatype.
 const base::Feature kSyncUSSNigori{"SyncUSSNigori",
-                                   base::FEATURE_DISABLED_BY_DEFAULT};
+                                   base::FEATURE_ENABLED_BY_DEFAULT};
 
 // Controls whether to enable syncing of Wi-Fi configurations.
 const base::Feature kSyncWifiConfigurations{"SyncWifiConfigurations",