Fix the clang bot.

chrome/browser/chromeos/login/mock_authenticator.h

Index: chrome/browser/chromeos/login/mock_authenticator.h
diff --git a/chrome/browser/chromeos/login/mock_authenticator.h b/chrome/browser/chromeos/login/mock_authenticator.h
index b54e7452fc165f649022dfb7e430fd479ed3e320..16c98b5319f9a4ad4dcf0f2bf5db1f724beb30cd 100644
--- a/chrome/browser/chromeos/login/mock_authenticator.h
+++ b/chrome/browser/chromeos/login/mock_authenticator.h
@@ -67,13 +67,9 @@ class MockAuthenticator : public Authenticator {
                          const std::string& login_token,
                          const std::string& login_captcha) {}
 
-  virtual std::string EncryptToken(const std::string& token) {
-    return std::string();
-  }
+  virtual std::string EncryptToken(const std::string& token);
 
-  virtual std::string DecryptToken(const std::string& encrypted_token) {
-    return std::string();
-  }
+  virtual std::string DecryptToken(const std::string& encrypted_token);
 
   virtual void VerifyOAuth1AccessToken(const std::string& oauth1_access_token,
                                        const std::string& oauth1_secret) {}