sync: avoid creating a HistoryModelWorker unless it is needed.

chrome/browser/sync/profile_sync_service_password_unittest.cc

Index: chrome/browser/sync/profile_sync_service_password_unittest.cc
diff --git a/chrome/browser/sync/profile_sync_service_password_unittest.cc b/chrome/browser/sync/profile_sync_service_password_unittest.cc
index dfb172b0fe1ad120e35dbcb23e2068a245fb708f..899b40c9c6310dae12ba23e90c2ef735172598e5 100644
--- a/chrome/browser/sync/profile_sync_service_password_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_password_unittest.cc
@@ -166,13 +166,6 @@ class ProfileSyncServicePasswordTest : public AbstractProfileSyncServiceTest {
       EXPECT_CALL(profile_, GetTokenService()).
           WillRepeatedly(Return(&token_service_));
 
-      // Creating model safe workers will request the history service and
-      // password store.  I couldn't manage to convince gmock that splitting up
-      // the expectations to match the class responsibilities was a good thing,
-      // so we set them all together here.
-      EXPECT_CALL(profile_, GetHistoryService(_)).
-         WillOnce(Return(static_cast<HistoryService*>(NULL)));
-
       EXPECT_CALL(profile_, GetPasswordStore(_)).
           Times(2).
           WillRepeatedly(Return(password_store_.get()));