Wrap ScreenCapturer with ScreenCapturerDifferWrapper

webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
index e4b2c3e8a225b397d4c67693baa646c2c98c34f3..9e3f58b11eb9896c87d01cef98fd8a407a133057 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.cc
@@ -21,6 +21,7 @@ namespace webrtc {
 
 using Microsoft::WRL::ComPtr;
 
+// static
 bool ScreenCapturerWinDirectx::IsSupported() {
   // Forward IsSupported function call to DxgiDuplicatorController.
   return DxgiDuplicatorController::Instance()->IsSupported();