Switch DesktopEnvironment to return a DesktopCapturer.

remoting/host/desktop_session_proxy.cc

Index: remoting/host/desktop_session_proxy.cc
diff --git a/remoting/host/desktop_session_proxy.cc b/remoting/host/desktop_session_proxy.cc
index 5094a7754b866ba2ef55d3993663a8417e2076f9..4cda02a53e9789d31ddd105996e70915e89982ce 100644
--- a/remoting/host/desktop_session_proxy.cc
+++ b/remoting/host/desktop_session_proxy.cc
@@ -139,10 +139,10 @@ scoped_ptr<ScreenControls> DesktopSessionProxy::CreateScreenControls() {
   return scoped_ptr<ScreenControls>(new IpcScreenControls(this));
 }
 
-scoped_ptr<webrtc::ScreenCapturer> DesktopSessionProxy::CreateVideoCapturer() {
+scoped_ptr<webrtc::DesktopCapturer> DesktopSessionProxy::CreateVideoCapturer() {
   DCHECK(caller_task_runner_->BelongsToCurrentThread());
 
-  return scoped_ptr<webrtc::ScreenCapturer>(new IpcVideoFrameCapturer(this));
+  return scoped_ptr<webrtc::DesktopCapturer>(new IpcVideoFrameCapturer(this));
 }
 
 scoped_ptr<webrtc::MouseCursorMonitor>