Create setting that disables password stores

components/os_crypt/key_storage_util_linux.h

Index: components/os_crypt/key_storage_util_linux.h
diff --git a/components/os_crypt/key_storage_util_linux.h b/components/os_crypt/key_storage_util_linux.h
index d5c04b6e70b8e8a36be3be6c1d428276704a40e4..f91bfc6867300e01649c3a7cf55c74774cb92137 100644
--- a/components/os_crypt/key_storage_util_linux.h
+++ b/components/os_crypt/key_storage_util_linux.h
@@ -9,6 +9,10 @@
 
 #include "base/nix/xdg_util.h"
 
+namespace base {
+class FilePath;
+}
+
 namespace os_crypt {
 
 // The supported Linux backends for storing passwords.
@@ -23,13 +27,22 @@ enum class SelectedLinuxBackend {
 };
 
 // Decide which backend to target. |type| is checked first. If it does not
-// match a supported backend, |desktop_env| will be used to decide.
+// match a supported backend and |use_backend| is true, |desktop_env| will be
+// used to decide.
 // TODO(crbug/571003): This is exposed as a utility only for password manager to
 // use. It should be merged into key_storage_linux, once no longer needed in
 // password manager.
 SelectedLinuxBackend SelectBackend(const std::string& type,
+                                   bool use_backend,
                                    base::nix::DesktopEnvironment desktop_env);
 
+// Set the setting that disables using OS-level encryption. If |use| is true,
+// a backend will be used.
+bool WriteBackendUse(const base::FilePath& user_data_dir, bool use);
+
+// Decide whether the backend should be used based on the setting.
+bool GetBackendUse(const base::FilePath& user_data_dir);
+
 }  // namespace os_crypt
 
 #endif  // COMPONENTS_OS_CRYPT_KEY_STORAGE_UTIL_LINUX_H_