Simplify ScreenCapturer interface.

remoting/host/ipc_video_frame_capturer.cc

Index: remoting/host/ipc_video_frame_capturer.cc
diff --git a/remoting/host/ipc_video_frame_capturer.cc b/remoting/host/ipc_video_frame_capturer.cc
index 24383f1ee44bace09d9998c585dcbcd1c2d18fae..5d1016f9307580cbcd7a8a708330f66b6aa0b45c 100644
--- a/remoting/host/ipc_video_frame_capturer.cc
+++ b/remoting/host/ipc_video_frame_capturer.cc
@@ -25,15 +25,6 @@ void IpcVideoFrameCapturer::Start(Delegate* delegate) {
   desktop_session_proxy_->SetVideoCapturer(weak_factory_.GetWeakPtr());
 }
 
-void IpcVideoFrameCapturer::Stop() {
-  delegate_ = NULL;
-  weak_factory_.InvalidateWeakPtrs();
-}
-
-void IpcVideoFrameCapturer::InvalidateRegion(const SkRegion& invalid_region) {
-  desktop_session_proxy_->InvalidateRegion(invalid_region);
-}
-
 void IpcVideoFrameCapturer::CaptureFrame() {
   desktop_session_proxy_->CaptureFrame();
 }