Add reference counter of DxgiDuplicatorController to unload DXGI components

webrtc/modules/desktop_capture/screen_capturer_win.cc

Index: webrtc/modules/desktop_capture/screen_capturer_win.cc
diff --git a/webrtc/modules/desktop_capture/screen_capturer_win.cc b/webrtc/modules/desktop_capture/screen_capturer_win.cc
index d8aecb15c7e86a6f5c124504f1c72f569baa9b7c..80e1ea358e78d3fb3f376ca857fd92c2a4d8ee5b 100644
--- a/webrtc/modules/desktop_capture/screen_capturer_win.cc
+++ b/webrtc/modules/desktop_capture/screen_capturer_win.cc
@@ -27,7 +27,7 @@ namespace {
 std::unique_ptr<DesktopCapturer> CreateScreenCapturerWinDirectx(
     const DesktopCaptureOptions& options) {
   std::unique_ptr<DesktopCapturer> capturer(
-      new ScreenCapturerWinDirectx(options));
+      new ScreenCapturerWinDirectx());
   capturer.reset(new BlankDetectorDesktopCapturerWrapper(
       std::move(capturer), RgbaColor(0, 0, 0, 0)));
   return capturer;
@@ -39,10 +39,14 @@ std::unique_ptr<DesktopCapturer> CreateScreenCapturerWinDirectx(
 std::unique_ptr<DesktopCapturer> DesktopCapturer::CreateRawScreenCapturer(
     const DesktopCaptureOptions& options) {
   std::unique_ptr<DesktopCapturer> capturer(new ScreenCapturerWinGdi(options));
-  if (options.allow_directx_capturer() &&
-      ScreenCapturerWinDirectx::IsSupported()) {
-    capturer.reset(new FallbackDesktopCapturerWrapper(
-        CreateScreenCapturerWinDirectx(options), std::move(capturer)));
+  if (options.allow_directx_capturer()) {
+    // |directx_capturer| should be alive in this scope to ensure it won't
+    // unload DxgiDuplicatorController.
+    ScreenCapturerWinDirectx directx_capturer;
+    if (directx_capturer.IsAvailable()) {
+      capturer.reset(new FallbackDesktopCapturerWrapper(
+          CreateScreenCapturerWinDirectx(options), std::move(capturer)));
+    }
   }
 
   if (options.allow_use_magnification_api()) {