Add AES-ECB as a supported encryption mode in ECMG

common/rsa_key.h

@@ -125,6 +125,9 @@ class RsaPublicKey {
   // Returns the RSA key size (modulus) in bytes.
   virtual uint32_t KeySize() const;
 
+  // Returns true if the key is successfully serialized into |serialized_key|.
+  virtual bool SerializedKey(std::string* serialized_key) const;
+
  private:
   friend class RsaPrivateKey;
   friend class X509CertificateBuilder;  // TODO(user): Get rid of this.