Introduce SigninManagerDelegate and use to eliminate CookieSettings dependency.

chrome/browser/signin/signin_manager_base.h

Index: chrome/browser/signin/signin_manager_base.h
diff --git a/chrome/browser/signin/signin_manager_base.h b/chrome/browser/signin/signin_manager_base.h
index cca866e2df6b2d2360011935f8044e45d1627903..b10e90f5de44b42d044734ce395e52f89cc2c048 100644
--- a/chrome/browser/signin/signin_manager_base.h
+++ b/chrome/browser/signin/signin_manager_base.h
@@ -62,11 +62,6 @@ struct GoogleServiceSignoutDetails {
 
 class SigninManagerBase : public ProfileKeyedService {
  public:
-  // Returns true if the cookie policy for the given profile allows cookies
-  // for the Google signin domain.
-  static bool AreSigninCookiesAllowed(Profile* profile);
-  static bool AreSigninCookiesAllowed(CookieSettings* cookie_settings);
-
   // Returns true if the username is allowed based on the policy string.
   static bool IsAllowedUsername(const std::string& username,
                                 const std::string& policy);