Updating D2D protocol to v1 to support separate sequence numbers.

components/cryptauth/device_to_device_secure_context.h

Index: components/cryptauth/device_to_device_secure_context.h
diff --git a/components/cryptauth/device_to_device_secure_context.h b/components/cryptauth/device_to_device_secure_context.h
index 0b59033cdc46444f514bab1275cf30a547d24971..e84b6cc54c069d6b4aa9b148f18e22dcbf9a0e17 100644
--- a/components/cryptauth/device_to_device_secure_context.h
+++ b/components/cryptauth/device_to_device_secure_context.h
@@ -18,13 +18,14 @@ class Header;
 namespace cryptauth {
 
 class SecureMessageDelegate;
+class SessionKeys;
 
 // SecureContext implementation for the DeviceToDevice protocol.
 class DeviceToDeviceSecureContext : public SecureContext {
  public:
   DeviceToDeviceSecureContext(
       std::unique_ptr<SecureMessageDelegate> secure_message_delegate,
-      const std::string& symmetric_key,
+      std::unique_ptr<SessionKeys> session_keys,
       const std::string& responder_auth_message_,
       ProtocolVersion protocol_version);
 
@@ -51,8 +52,8 @@ class DeviceToDeviceSecureContext : public SecureContext {
   // Delegate for handling the creation and unwrapping of SecureMessages.
   std::unique_ptr<SecureMessageDelegate> secure_message_delegate_;
 
-  // The symmetric key used to create and unwrap messages.
-  const std::string symmetric_key_;
+  // The symmetric keys used to create and unwrap messages.
+  std::unique_ptr<SessionKeys> session_keys_;
 
   // The [Responder Auth] message received from the remote device during
   // authentication.
@@ -61,8 +62,11 @@ class DeviceToDeviceSecureContext : public SecureContext {
   // The protocol version supported by the remote device.
   const ProtocolVersion protocol_version_;
 
-  // The last sequence number of the message sent or received.
-  int last_sequence_number_;
+  // The last sequence number of the message sent.
+  int last_encode_sequence_number_;
+
+  // The last sequence number of the message received.
+  int last_decode_sequence_number_;
 
   base::WeakPtrFactory<DeviceToDeviceSecureContext> weak_ptr_factory_;