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

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_
 
 #include "webrtc/modules/desktop_capture/screen_capturer.h"
 
+#include <D3DCommon.h>
+
 #include <memory>
 #include <vector>
 
 #include "webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "webrtc/modules/desktop_capture/desktop_region.h"
 #include "webrtc/modules/desktop_capture/screen_capture_frame_queue.h"
 #include "webrtc/modules/desktop_capture/shared_desktop_frame.h"
 #include "webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.h"
 
 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:
+  using D3dInfo = DxgiDuplicatorController::D3dInfo;
+
   // Whether the system supports DirectX based capturing.
   static bool IsSupported();
 
+  // Returns a most recent D3dInfo composed by
+  // DxgiDuplicatorController::Initialize() function. This function implicitly
+  // calls DxgiDuplicatorController::Initialize() if it has not been
+  // initialized. This function returns false and output parameter is kept
+  // unchanged if DxgiDuplicatorController::Initialize() failed.
+  // The D3dInfo may change based on hardware configuration even without
+  // restarting the hardware and software. Refer to https://goo.gl/OOCppq. So
+  // consumers should not cache the result returned by this function.
+  static bool RetrieveD3dInfo(D3dInfo* info);
+
   explicit ScreenCapturerWinDirectx(const DesktopCaptureOptions& options);
 
   ~ScreenCapturerWinDirectx() override;
 
   void Start(Callback* callback) override;
   void SetSharedMemoryFactory(
       std::unique_ptr<SharedMemoryFactory> shared_memory_factory) override;
   void CaptureFrame() override;
   bool GetScreenList(ScreenList* screens) override;
   bool SelectScreen(ScreenId id) override;
 
  private:
   // Returns desktop size of selected screen.
   DesktopSize SelectedDesktopSize() const;
 
   ScreenCaptureFrameQueue<SharedDesktopFrame> frames_;
   std::unique_ptr<SharedMemoryFactory> shared_memory_factory_;
   Callback* callback_ = nullptr;
 
   DxgiDuplicatorController::Context context_;
 
   ScreenId current_screen_id_ = kFullDesktopScreenId;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(ScreenCapturerWinDirectx);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURER_WIN_DIRECTX_H_