[Sync] Add a sanity integration test for USS.

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 33de5dba7914226552f5258240e60f72e13e97ab..2f3381825a8c1925dfe56b0848a7d36ba68e8d56 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -897,6 +897,7 @@ if (!is_android) {
       "//components/invalidation/impl",
       "//components/invalidation/impl:test_support",
       "//components/sync",
+      "//components/sync:test_support_sync_api",
       "//components/sync:test_support_sync_fake_server",
       "//components/sync:test_support_sync_testserver",
       "//content/test:test_support",
@@ -2681,6 +2682,7 @@ if (!is_android) {
       "../browser/sync/test/integration/two_client_sessions_sync_test.cc",
       "../browser/sync/test/integration/two_client_themes_sync_test.cc",
       "../browser/sync/test/integration/two_client_typed_urls_sync_test.cc",
+      "../browser/sync/test/integration/two_client_uss_sync_test.cc",
       "../browser/sync/test/integration/two_client_wifi_credentials_sync_test.cc",
       "data/resource.rc",
     ]