Output DeviceName from various windows ScreenCapturer related implementations

webrtc/modules/desktop_capture/win/screen_capture_utils.h

Index: webrtc/modules/desktop_capture/win/screen_capture_utils.h
diff --git a/webrtc/modules/desktop_capture/win/screen_capture_utils.h b/webrtc/modules/desktop_capture/win/screen_capture_utils.h
index 751588b47e63640fded00c9da1648bd8d5d9c467..90dd38ff22c60c57a5e0c7405e0a4aeb3385e00f 100644
--- a/webrtc/modules/desktop_capture/win/screen_capture_utils.h
+++ b/webrtc/modules/desktop_capture/win/screen_capture_utils.h
@@ -11,13 +11,20 @@
 #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