Add base:: to string16s in chrome/.

chrome/test/base/testing_profile_manager.h

Index: chrome/test/base/testing_profile_manager.h
diff --git a/chrome/test/base/testing_profile_manager.h b/chrome/test/base/testing_profile_manager.h
index 5a0dd28b8854dabbc6fd26f5b32e8b9ceb7e2f25..b4c1dda39d3197ce30a4a4719699b218f657d498 100644
--- a/chrome/test/base/testing_profile_manager.h
+++ b/chrome/test/base/testing_profile_manager.h
@@ -52,7 +52,7 @@ class TestingProfileManager {
   TestingProfile* CreateTestingProfile(
       const std::string& profile_name,
       scoped_ptr<PrefServiceSyncable> prefs,
-      const string16& user_name,
+      const base::string16& user_name,
       int avatar_id,
       const std::string& managed_user_id,
       const TestingProfile::TestingFactories& factories);