Skips the first frame in DxgiDuplicatorController

webrtc/modules/desktop_capture/win/dxgi_duplicator_controller.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.
  */
 
@@ skipping 153 matching lines @@
   // Clears all COM components referred by this instance. So next Duplicate()
   // call will eventually initialize this instance again.
   void Deinitialize();
 
   // A helper function to check whether a Context has been expired.
   bool ContextExpired(const Context* const context) const;
 
   // Updates Context if needed.
   void Setup(Context* context);
 
-  // Do the real duplication work. |monitor_id < 0| to capture entire screen.
+  // Does the real duplication work. |monitor_id < 0| to capture entire screen.
   bool DoDuplicate(Context* context,
                    int monitor_id,
                    SharedDesktopFrame* target);
 
   bool DoDuplicateUnlocked(Context* context,
                            int monitor_id,
                            SharedDesktopFrame* target);
 
+  // Captures all monitors.
+  bool DoDuplicateAll(Context* context, SharedDesktopFrame* target);
+
+  // Captures one monitor.
+  bool DoDuplicateOne(Context* context,
+                      int monitor_id,
+                      SharedDesktopFrame* target);
+
+  // The minimum GetNumFramesCaptured() returned by |duplicators_|.
+  int64_t GetNumFramesCaptured() const;
+
+  int ScreenCountUnlocked();
+
+  // Retries DoDuplicateAll() for several times until GetNumFramesCaptured() is
+  // large enough. Returns false if DoDuplicateAll() returns false, or
+  // GetNumFramesCaptured() has never reached the requirement.
+  // According to http://crbug.com/682112, dxgi capturer returns a black frame
+  // during first several capture attempts.
+  bool EnsureFrameCaptured(Context* context, SharedDesktopFrame* target);
+
   // This lock must be locked whenever accessing any of the following objects.
   rtc::CriticalSection lock_;
 
   // A self-incremented integer to compare with the one in Context, to
   // ensure a Context has been initialized after DxgiDuplicatorController.
   int identity_ = 0;
   DesktopRect desktop_rect_;
   DesktopVector dpi_;
   std::vector<DxgiAdapterDuplicator> duplicators_;
   D3dInfo d3d_info_;
   ResolutionChangeDetector resolution_change_detector_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_DXGI_DUPLICATOR_CONTROLLER_H_