Wait for Cryptohome service to be available on login.

chrome/browser/chromeos/login/existing_user_controller.h

Index: chrome/browser/chromeos/login/existing_user_controller.h
diff --git a/chrome/browser/chromeos/login/existing_user_controller.h b/chrome/browser/chromeos/login/existing_user_controller.h
index 32f8a497364c3e69c7bb2354b48da675ea897c42..c47e79f5783646d58a381f34c4f07bbc35d9a681 100644
--- a/chrome/browser/chromeos/login/existing_user_controller.h
+++ b/chrome/browser/chromeos/login/existing_user_controller.h
@@ -251,6 +251,11 @@ class ExistingUserController
   // auto-login timer is started.
   void PerformLoginFinishedActions(bool start_auto_login_timer);
 
+  // Invokes |continuation| after verifying that cryptohome service is
+  // available.
+  void ContinueLoginWhenCryptohomeAvailable(base::OnceClosure continuation,
+                                            bool service_is_available);
+
   // Invokes |continuation| after verifying that the device is not disabled.
   void ContinueLoginIfDeviceNotDisabled(const base::Closure& continuation);