Remove the requirement of D3D_FEATURE_LEVEL_11_0, but export the D3D_FEATURE_LEVEL through APIs

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h

Index: webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
diff --git a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
index 1abfe81d920fa07ca867573ca4c29a80fe8ad38b..90b7d076bb31a6931e2709ad35271725e01404f4 100644
--- a/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
+++ b/webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h
@@ -11,6 +11,8 @@
 #ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_DUPLICATOR_CONTROLLER_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_DUPLICATOR_CONTROLLER_H_
 
+#include <D3DCommon.h>
+
 #include <memory>
 #include <vector>
 
@@ -67,6 +69,10 @@ class DxgiDuplicatorController {
   // Detects whether the system supports DXGI based capturer.
   bool IsSupported();
 
+  // Returns minimum and maximum D3D_FEATURE_LEVEL current system supports.
+  bool SupportedFeatureLevels(D3D_FEATURE_LEVEL* min_feature_level,
+                              D3D_FEATURE_LEVEL* max_feature_level);
+
   // Captures current screen and writes into target. Since we are using double
   // buffering, |last_frame|.updated_region() is used to represent the not
   // updated regions in current |target| frame, which should also be copied this
@@ -153,6 +159,8 @@ class DxgiDuplicatorController {
   DesktopRect desktop_rect_;
   DesktopVector dpi_;
   std::vector<DxgiAdapterDuplicator> duplicators_;
+  D3D_FEATURE_LEVEL min_feature_level_;
+  D3D_FEATURE_LEVEL max_feature_level_;
 };
 
 }  // namespace webrtc