[Chromoting] Remove DataChannelManagerCallbacks constructor parameter of ClientSession

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 3e2ce47a3855cecfa1ab73a8f3228ae54fc71160..4bfd9e2b994a85513d6bcd3afb1adcc14451b06f 100644
--- a/remoting/host/chromoting_host.cc
+++ b/remoting/host/chromoting_host.cc
@@ -263,8 +263,7 @@ void ChromotingHost::OnIncomingSession(
   clients_.push_back(base::MakeUnique<ClientSession>(
       this, std::move(connection), desktop_environment_factory_,
       desktop_environment_options_, max_session_duration_, pairing_registry_,
-      extension_ptrs,
-      std::vector<protocol::DataChannelManager::NameCallbackPair>()));

[jarhar, 2017/07/05 17:51:42]

In order to register callbacks from this file, would you call
ClientSession::RegisterDataChannelManagerCallback() here before adding new
clients to clients_?

like this:
std::unique_ptr<ClientSession> new_client = base::MakeUnique(...);
new_client->RegisterDataChannelManagerCallback(...);
clients_.push_back(std::move(new_client));

[Hzj_jie, 2017/07/05 18:34:31]

That's usually not necessary: Optional data channels and their callbacks won't
take effect before authentication.

+      extension_ptrs));
 }
 
 }  // namespace remoting