Simplify ScreenCapturer interface.

media/video/capture/screen/screen_capturer_x11.cc

Index: media/video/capture/screen/screen_capturer_x11.cc
diff --git a/media/video/capture/screen/screen_capturer_x11.cc b/media/video/capture/screen/screen_capturer_x11.cc
index b4bfaeb55ecf65dc06f07726d92040c94bbd3651..f9da3b3533e4e1ede7054ba59da750c3187e43ab 100644
--- a/media/video/capture/screen/screen_capturer_x11.cc
+++ b/media/video/capture/screen/screen_capturer_x11.cc
@@ -52,8 +52,6 @@ class ScreenCapturerLinux : public ScreenCapturer {
 
   // Capturer interface.
   virtual void Start(Delegate* delegate) OVERRIDE;
-  virtual void Stop() OVERRIDE;
-  virtual void InvalidateRegion(const SkRegion& invalid_region) OVERRIDE;
   virtual void CaptureFrame() OVERRIDE;
 
  private:
@@ -278,13 +276,6 @@ void ScreenCapturerLinux::Start(Delegate* delegate) {
   delegate_ = delegate;
 }
 
-void ScreenCapturerLinux::Stop() {
-}
-
-void ScreenCapturerLinux::InvalidateRegion(const SkRegion& invalid_region) {
-  helper_.InvalidateRegion(invalid_region);
-}
-
 void ScreenCapturerLinux::CaptureFrame() {
   base::Time capture_start_time = base::Time::Now();