[Chromoting] Make ChromotingHost's dependency on libjingle injected, instead of hard-coded.

remoting/host/session_manager_factory.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/host/session_manager_factory.h"
+
+#include "net/url_request/url_request_context_getter.h"
+#include "remoting/host/host_port_allocator.h"
+#include "remoting/host/network_settings.h"
+#include "remoting/protocol/libjingle_transport_factory.h"
+#include "remoting/protocol/jingle_session_manager.h"
+
+namespace remoting {
+
+scoped_ptr<protocol::SessionManager> CreateHostSessionManager(
+    const NetworkSettings& network_settings,
+    const scoped_refptr<net::URLRequestContextGetter>&
+        url_request_context_getter) {
+  // Use Chrome's network stack to allocate ports for peer-to-peer channels.
+  scoped_ptr<HostPortAllocator> port_allocator(
+      HostPortAllocator::Create(url_request_context_getter,
+                                network_settings));
+
+  bool incoming_only = network_settings.nat_traversal_mode ==
+      NetworkSettings::NAT_TRAVERSAL_DISABLED;
+
+  // Use libjingle for negotiation of peer-to-peer channels over
+  // HostPortAllocator allocated ports.
+  scoped_ptr<protocol::TransportFactory> transport_factory(
+      new protocol::LibjingleTransportFactory(
+          port_allocator.PassAs<cricket::HttpPortAllocatorBase>(),
+          incoming_only));
+
+  // Use the Jingle protocol for channel-negotiation signalling between
+  // peer TransportFactories.
+  bool fetch_stun_relay_info = network_settings.nat_traversal_mode ==
+      NetworkSettings::NAT_TRAVERSAL_ENABLED;
+
+  scoped_ptr<protocol::JingleSessionManager> session_manager(
+      new protocol::JingleSessionManager(
+          transport_factory.Pass(), fetch_stun_relay_info));
+  return session_manager.PassAs<protocol::SessionManager>();
+}
+
+} // namespace remoting