Update TPMTokenLoader class comment.

BUG=210525

Review URL: https://codereview.chromium.org/386593002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282822 0039d316-1c4b-4281-b951-d872f2087c98

chromeos/tpm_token_loader.h

@@ -23,11 +23,13 @@ class SequencedTaskRunner;
 
 namespace chromeos {
 
-// This class is responsible for loading the TPM token when the user logs
-// in. It is expected to be constructed on the UI thread and public methods
-// should all be called from the UI thread. When the TPM token is loaded,
-// or if the TPM should stay disabled for the session, the observers are
-// notified using |OnTPMTokenReady|.
+// This class is responsible for loading the TPM backed token for the system
+// slot when the user logs in. It is expected to be constructed on the UI thread
+// and public methods should all be called from the UI thread.
+// When the TPM token is loaded, or if the TPM should stay disabled for the
+// session, the observers are notified using |OnTPMTokenReady|.
+// Note: This currently initializes the token with the hard coded default id 0.
+// See CryptohomeClient::OnPkcs11GetTpmTokenInfo.
 class CHROMEOS_EXPORT TPMTokenLoader : public LoginState::Observer {
  public:
   class Observer {