Output DeviceName from various windows ScreenCapturer related implementations

webrtc/modules/desktop_capture/win/screen_capture_utils.h

 /*
  *  Copyright (c) 2014 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_CAPTURE_UTILS_H_
 #define WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURE_UTILS_H_
 
+#include <vector>
+#include <string>
+
 #include "webrtc/modules/desktop_capture/desktop_capturer.h"
 
 namespace webrtc {
 
 // Output the list of active screens into |screens|. Returns true if succeeded,
-// or false if it fails to enumerate the display devices.
-bool GetScreenList(DesktopCapturer::SourceList* screens);
+// or false if it fails to enumerate the display devices. If the |device_names|
+// is provided, it will be filled with the DISPLAY_DEVICE.DeviceName in UTF-8
+// encoding. Once this function returns true, consumers can always assume that
+// |screens|[i] and |device_names|[i] indicate the same monitor on the system.
+bool GetScreenList(DesktopCapturer::SourceList* screens,
+                   std::vector<std::string>* device_names = nullptr);
 
 // Returns true if |screen| is a valid screen. The screen device key is
 // returned through |device_key| if the screen is valid. The device key can be
 // used in GetScreenRect to verify the screen matches the previously obtained
 // id.
 bool IsScreenValid(DesktopCapturer::SourceId screen, std::wstring* device_key);
 
 // Get the rect of the screen identified by |screen|, relative to the primary
 // display's top-left. If the screen device key does not match |device_key|, or
 // the screen does not exist, or any error happens, an empty rect is returned.
 DesktopRect GetScreenRect(DesktopCapturer::SourceId screen,
                           const std::wstring& device_key);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_WIN_SCREEN_CAPTURE_UTILS_H_