ChromeOS: Add RenameCryptohome and migration code.

chromeos/dbus/cryptohome_client.h

Index: chromeos/dbus/cryptohome_client.h
diff --git a/chromeos/dbus/cryptohome_client.h b/chromeos/dbus/cryptohome_client.h
index 233ff9375aaacbb2b885a88238f59a849cd9874c..15ce84f5e9fb43c6584304f32d4f19b5e48a8604 100644
--- a/chromeos/dbus/cryptohome_client.h
+++ b/chromeos/dbus/cryptohome_client.h
@@ -139,6 +139,13 @@ class CHROMEOS_EXPORT CryptohomeClient : public DBusClient {
   virtual void AsyncRemove(const cryptohome::Identification& cryptohome_id,
                            const AsyncMethodCallback& callback) = 0;
 
+  // Calls RenameCryptohome method. |callback| is called after the method
+  // call succeeds.
+  virtual void RenameCryptohome(
+      const cryptohome::Identification& cryptohome_id_from,
+      const cryptohome::Identification& cryptohome_id_to,
+      const ProtobufMethodCallback& callback) = 0;
+
   // Calls GetSystemSalt method.  |callback| is called after the method call
   // succeeds.
   virtual void GetSystemSalt(const GetSystemSaltCallback& callback) = 0;