Replace direct access to kGoogleServicesUsername with calls to SigninManager.

chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc

Index: chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc
diff --git a/chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc b/chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc
index 662563770f0c05ba91f0742b29132ea136981edd..f444b22ee5e638792151c7dbc9cfaf52863e5c2e 100644
--- a/chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc
+++ b/chrome/browser/extensions/api/screenlock_private/screenlock_private_apitest.cc
@@ -3,8 +3,12 @@
 // found in the LICENSE file.
 
 #include "base/strings/string16.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/screenlock_private/screenlock_private_api.h"
 #include "chrome/browser/extensions/extension_apitest.h"
+#include "chrome/browser/profiles/profile_info_cache.h"
+#include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/signin/easy_unlock_service.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "components/signin/core/browser/signin_manager.h"
@@ -46,6 +50,11 @@ class ScreenlockPrivateApiTest : public ExtensionApiTest,
   void SetUpOnMainThread() override {
     SigninManagerFactory::GetForProfile(profile())
         ->SetAuthenticatedUsername(kTestUser);
+    ProfileInfoCache& info_cache =
+        g_browser_process->profile_manager()->GetProfileInfoCache();
+    size_t index = info_cache.GetIndexOfProfileWithPath(profile()->GetPath());
+    ASSERT_NE(std::string::npos, index);
+    info_cache.SetUserNameOfProfileAtIndex(index, base::UTF8ToUTF16(kTestUser));
     ExtensionApiTest::SetUpOnMainThread();
   }