cryptohome: Add dbus method and signal name for encryption migration.

chromeos/dbus/fake_cryptohome_client.h

Index: chromeos/dbus/fake_cryptohome_client.h
diff --git a/chromeos/dbus/fake_cryptohome_client.h b/chromeos/dbus/fake_cryptohome_client.h
index 1173e223ea6837d3923d893353c67d1b3c05cb6c..1a7f03dba7a3587bc3c793f1d9a5f2e0efd9795f 100644
--- a/chromeos/dbus/fake_cryptohome_client.h
+++ b/chromeos/dbus/fake_cryptohome_client.h
@@ -195,6 +195,11 @@ class CHROMEOS_EXPORT FakeCryptohomeClient : public CryptohomeClient {
   void FlushAndSignBootAttributes(
       const cryptohome::FlushAndSignBootAttributesRequest& request,
       const ProtobufMethodCallback& callback) override;
+  void MigrateToDircrypto(const cryptohome::Identification& cryptohome_id,
+                          const cryptohome::AuthorizationRequest& auth,
+                          const VoidDBusMethodCallback& callback) override;
+  void SetDircryptoMigrationProgressHandler(
+      const DircryptoMigrationProgessHandler& handler) override;
 
   // Changes the behavior of WaitForServiceToBeAvailable(). This method runs
   // pending callbacks if is_available is true.