Pass empty cros_user string to GetProfileSyncService() in sync integration tests

The sync integration tests are broken on chrome OS because a cros_string
is not being passed to GetProfileSyncService() in
ProfileSyncServiceHarness::SetupSync(), causing no ProfileSyncService
object to be returned.

This patch passes an empty cros_user string to GetProfileSyncService(),
thereby fixing the sync integration tests on chrome OS.

BUG=70854, chromium-os:11319, chromium-os:9262
TEST=sync_integration_tests

Review URL: http://codereview.chromium.org/6248019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72574 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync/profile_sync_service_harness.cc

@@ -130,7 +130,7 @@ bool ProfileSyncServiceHarness::SetupSync() {
 bool ProfileSyncServiceHarness::SetupSync(
     const syncable::ModelTypeSet& synced_datatypes) {
   // Initialize the sync client's profile sync service object.
-  service_ = profile_->GetProfileSyncService();
+  service_ = profile_->GetProfileSyncService("");
   if (service_ == NULL) {
     LOG(ERROR) << "SetupSync(): service_ is null.";
     return false;