Removes downgrade browser test hack and verifies renamed user data dir.

chrome/browser/downgrade/user_data_downgrade.h

Index: chrome/browser/downgrade/user_data_downgrade.h
diff --git a/chrome/browser/downgrade/user_data_downgrade.h b/chrome/browser/downgrade/user_data_downgrade.h
index 3ccd9290c87ead3964beb1852bc39bda972ae973..d137e25133f6d87aa00c5f47853c35152bbc3445 100644
--- a/chrome/browser/downgrade/user_data_downgrade.h
+++ b/chrome/browser/downgrade/user_data_downgrade.h
@@ -38,12 +38,6 @@ void DeleteMovedUserDataSoon();
 // Returns true if Chrome is installed by MSI.
 bool IsMSIInstall();
 
-// Changes the behavior of the above functions to simulate a downgrade for use
-// in tests. MoveUserDataForFirstRunAfterDowngrade will no longer rely on
-// registry and DeleteMovedUserDataSoon will always post task into blocking
-// pool for brower test.
-void SetSimulateDowngradeForTest(bool is_browser_test);
-
 }  // namespace downgrade
 
 #endif  // CHROME_BROWSER_DOWNGRADE_USER_DATA_DOWNGRADE_H_