[calls] dummy: Add dummy send_dtmf_tone function

[Evangelos Ribeiro Tzaras <devrtz src gnome org>]

commit 4c2717c36218be699b1ed766f10a20f6f19fed8c
Author: Evangelos Ribeiro Tzaras <devrtz fortysixandtwo eu>
Date:   Tue Nov 16 14:06:34 2021 +0100

    dummy: Add dummy send_dtmf_tone function
    
    This will allow DTMF to be tested UI wise when running the dummy plugin.

 plugins/dummy/calls-dummy-call.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/plugins/dummy/calls-dummy-call.c b/plugins/dummy/calls-dummy-call.c
index 3df58877..c0ce07b5 100644
--- a/plugins/dummy/calls-dummy-call.c
+++ b/plugins/dummy/calls-dummy-call.c
@@ -124,6 +124,13 @@ calls_dummy_call_hang_up (CallsCall *call)
   change_state (self, CALLS_CALL_STATE_DISCONNECTED);
 }
 
+static void
+calls_dummy_call_send_dtmf_tone (CallsCall *call,
+                                 char       key)
+{
+  g_debug ("Beep! (%c)", key);
+}
+
 static gboolean
 outbound_timeout_cb (CallsDummyCall *self)
 {
@@ -231,6 +238,7 @@ calls_dummy_call_class_init (CallsDummyCallClass *klass)
   call_class->get_protocol = calls_dummy_call_get_protocol;
   call_class->answer = calls_dummy_call_answer;
   call_class->hang_up = calls_dummy_call_hang_up;
+  call_class->send_dtmf_tone = calls_dummy_call_send_dtmf_tone;
 
   props[PROP_NUMBER_CONSTRUCTOR] =
     g_param_spec_string ("number-constructor",