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

webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h

Index: webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
diff --git a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
index c84aac086f2e7d9f79079395462d46124a1427b9..21f3b5a2094d7a477b3adf5e46e4be77989601fc 100644
--- a/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
+++ b/webrtc/modules/desktop_capture/win/screen_capturer_win_directx.h
@@ -13,6 +13,8 @@
 
 #include "webrtc/modules/desktop_capture/screen_capturer.h"
 
+#include <D3DCommon.h>
+
 #include <memory>
 #include <vector>
 
@@ -24,13 +26,22 @@
 
 namespace webrtc {
 
-// ScreenCapturerWinDirectx captures 32bit RGBA using DirectX. This
-// implementation won't work when ScreenCaptureFrameQueue.kQueueLength is not 2.
+// ScreenCapturerWinDirectx captures 32bit RGBA using DirectX.
 class ScreenCapturerWinDirectx : public ScreenCapturer {
  public:
   // Whether the system supports DirectX based capturing.
   static bool IsSupported();
 
+  // Each video adapter has its own D3D_FEATURE_LEVEL, so this function
+  // retrieves the minimum and maximium D3D_FEATURE_LEVELs current system
+  // supports. This function implicitly calls
+  // DxgiDuplicatorController::Initialize() if it has not been initialized. This
+  // function returns false and both output parameters are kept unchanged if
+  // DxgiDuplicatorController::Initialize() failed. Both |min_feature_level| and
+  // |max_feature_level| can be nullptr.
+  static bool SupportedFeatureLevels(D3D_FEATURE_LEVEL* min_feature_level,

[Sergey Ulanov, 2016/11/07 19:37:16]

Maybe we should expose some other hardware info here? E.g. manufacturer name,
driver version, etc? If so then it's probably better to do it with a single
method.

[Hzj_jie, 2016/11/08 01:25:40]

Yes, I have added a D3dInfo structure for further extension.

+                                     D3D_FEATURE_LEVEL* max_feature_level);
+
   explicit ScreenCapturerWinDirectx(const DesktopCaptureOptions& options);
 
   ~ScreenCapturerWinDirectx() override;