[sync]sync_integration_tests using python server fail

components/sync/test/local_sync_test_server.cc

Index: components/sync/test/local_sync_test_server.cc
diff --git a/components/sync/test/local_sync_test_server.cc b/components/sync/test/local_sync_test_server.cc
index 4dd1bfd09a9c63a7439ea9b362c60200eedc87df..dace9e6179012b39878d518f91502e4f15a26a07 100644
--- a/components/sync/test/local_sync_test_server.cc
+++ b/components/sync/test/local_sync_test_server.cc
@@ -37,6 +37,10 @@ LocalSyncTestServer::~LocalSyncTestServer() {}
 
 bool LocalSyncTestServer::AddCommandLineArguments(
     base::CommandLine* command_line) const {
+  // Suppress loading of site packages in order to avoid a version mismatch
+  // between pre-installed versions of python libraries.
+  // See https://bugs.chromium.org/p/chromium/issues/detail?id=649829
+  command_line->AppendSwitch("-S");
   if (!LocalTestServer::AddCommandLineArguments(command_line))
     return false;
   if (xmpp_port_ != 0) {