Cleanup usage of scoped_ptr<> in remoting for C++11

 - Use nullptr to initialize null scoped_ptr().
 - use Pass(), PassAs() is no longer required.

Review URL: https://codereview.chromium.org/609923004

Cr-Commit-Position: refs/heads/master@{#297236}
diff --git a/remoting/host/desktop_session_win.cc b/remoting/host/desktop_session_win.cc
index 6005b30..b147783 100644
--- a/remoting/host/desktop_session_win.cc
+++ b/remoting/host/desktop_session_win.cc
@@ -375,7 +375,7 @@
       caller_task_runner, io_task_runner, daemon_process, id,
       HostService::GetInstance()));
 
-  return session.PassAs<DesktopSession>();
+  return session.Pass();
 }
 
 // static
@@ -389,9 +389,9 @@
       caller_task_runner, io_task_runner, daemon_process, id,
       HostService::GetInstance()));
   if (!session->Initialize(resolution))
-    return scoped_ptr<DesktopSession>();
+    return nullptr;
 
-  return session.PassAs<DesktopSession>();
+  return session.Pass();
 }
 
 DesktopSessionWin::DesktopSessionWin(
@@ -552,8 +552,7 @@
   }
 
   // Create a launcher for the desktop process, using the per-session delegate.
-  launcher_.reset(new WorkerProcessLauncher(
-      delegate.PassAs<WorkerProcessLauncher::Delegate>(), this));
+  launcher_.reset(new WorkerProcessLauncher(delegate.Pass(), this));
 }
 
 void DesktopSessionWin::OnSessionDetached() {