Add clean up logic to navigator.credentials layout tests

components/test_runner/test_runner.h

Index: components/test_runner/test_runner.h
diff --git a/components/test_runner/test_runner.h b/components/test_runner/test_runner.h
index 9be952257a5662262c41614d365a5d201bd0fa7e..ac2ebd935dc57b3d32cf7d54b82bfe1b11ac8f5f 100644
--- a/components/test_runner/test_runner.h
+++ b/components/test_runner/test_runner.h
@@ -542,11 +542,12 @@ class TestRunner : public WebTestRunner {
 
   // Credential Manager mock functions
   // TODO(mkwst): Support FederatedCredential.
-  void AddMockCredentialManagerResponse(const std::string& id,
+  void SetMockCredentialManagerResponse(const std::string& id,
                                         const std::string& name,
                                         const std::string& avatar,
                                         const std::string& password);
-  void AddMockCredentialManagerError(const std::string& error);
+  void ClearMockCredentialManagerResponse();
+  void SetMockCredentialManagerError(const std::string& error);
 
   // Takes care of notifying the delegate after a change to layout test runtime
   // flags.