Add audible support to the copresence API.

components/copresence/handlers/directive_handler.cc

Index: components/copresence/handlers/directive_handler.cc
diff --git a/components/copresence/handlers/directive_handler.cc b/components/copresence/handlers/directive_handler.cc
index 01658528ff41e3c8bede15ab9f721510fd92ec81..a7ca573ed4c13e901e1e535eb172d4a26fc0cda4 100644
--- a/components/copresence/handlers/directive_handler.cc
+++ b/components/copresence/handlers/directive_handler.cc
@@ -27,12 +27,14 @@ void DirectiveHandler::AddDirective(const Directive& directive) {
   DCHECK_EQ(directive.instruction_type(), TOKEN);
 
   const TokenInstruction& ti = directive.token_instruction();
-  // We currently only support audio.
-  DCHECK_EQ(ti.medium(), AUDIO_ULTRASOUND_PASSBAND);
   DCHECK(audio_handler_.get()) << "Clients must call Initialize() before "
                                << "any other DirectiveHandler methods.";
-  audio_handler_->AddInstruction(
-      ti, base::TimeDelta::FromMilliseconds(directive.ttl_millis()));
+  // We currently only support audio.
+  if (ti.medium() == AUDIO_ULTRASOUND_PASSBAND ||
+      ti.medium() == AUDIO_AUDIBLE_DTMF) {
+    audio_handler_->AddInstruction(
+        ti, base::TimeDelta::FromMilliseconds(directive.ttl_millis()));
+  }
 }
 
 void DirectiveHandler::RemoveDirectives(const std::string& /* op_id */) {