Switch CandidateSession to use lists rather than vectors.

remoting/host/chromoting_host.cc

Index: remoting/host/chromoting_host.cc
diff --git a/remoting/host/chromoting_host.cc b/remoting/host/chromoting_host.cc
index 469c5b2849f824a9c2235a1fa705baddafe028b0..daefe4e5e8908856f871be86b34755d5a29ca5a4 100644
--- a/remoting/host/chromoting_host.cc
+++ b/remoting/host/chromoting_host.cc
@@ -86,13 +86,8 @@ ChromotingHost::ChromotingHost(
   DCHECK(network_task_runner_->BelongsToCurrentThread());
   DCHECK(signal_strategy);
 
-  // VP9 encode is not yet supported.
-  protocol::CandidateSessionConfig::DisableVideoCodec(
-      protocol_config_.get(), protocol::ChannelConfig::CODEC_VP9);
-
   if (!desktop_environment_factory_->SupportsAudioCapture()) {
-    protocol::CandidateSessionConfig::DisableAudioChannel(
-        protocol_config_.get());
+    protocol_config_->DisableAudioChannel();
   }
 }