[Chrome OS] Attempt offline and online login simultaneously

chrome/browser/chromeos/cros/cryptohome_library.h

Index: chrome/browser/chromeos/cros/cryptohome_library.h
diff --git a/chrome/browser/chromeos/cros/cryptohome_library.h b/chrome/browser/chromeos/cros/cryptohome_library.h
index 9a72761fc0fe0935e33eee395523bed388b89c83..5687c5c98229d91dc924c02a24dcbb6fa684a444 100644
--- a/chrome/browser/chromeos/cros/cryptohome_library.h
+++ b/chrome/browser/chromeos/cros/cryptohome_library.h
@@ -84,6 +84,10 @@ class CryptohomeLibrary {
   // d->OnComplete() will be called with status info on completion.
   virtual bool AsyncMountForBwsi(Delegate* callback) = 0;
 
+  // Asks cryptohomed to unmount the currently mounted cryptohome.
+  // Returns false if the cryptohome could not be unmounted, true otherwise.
+  virtual bool Unmount() = 0;
+
   // Asks cryptohomed to try to find the cryptohome for |user_email| and then
   // nuke it.
   virtual bool Remove(const std::string& user_email) = 0;