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

remoting/host/chromoting_host_unittest.cc

Index: remoting/host/chromoting_host_unittest.cc
diff --git a/remoting/host/chromoting_host_unittest.cc b/remoting/host/chromoting_host_unittest.cc
index b2b1bae8b65a137d3cd3bea356f56f8efab6148a..785c186647443f58daabbeaf67f67cf7dbf9da0b 100644
--- a/remoting/host/chromoting_host_unittest.cc
+++ b/remoting/host/chromoting_host_unittest.cc
@@ -92,10 +92,12 @@ class ChromotingHostTest : public testing::Test {
         &context_,
         capturer.Pass(),
         event_executor.Pass());
+    scoped_ptr<protocol::SessionManager> session_manager(
+        new protocol::MockSessionManager());
 
     host_ = new ChromotingHost(
         &context_, &signal_strategy_, desktop_environment_.get(),
-        NetworkSettings());
+        session_manager.Pass());
 
     disconnect_window_ = new MockDisconnectWindow();
     continue_window_ = new MockContinueWindow();