Output DeviceName from various windows ScreenCapturer related implementations

webrtc/modules/desktop_capture/win/screen_capture_utils.cc

 /*
  *  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.
  */
 
 #include "webrtc/modules/desktop_capture/win/screen_capture_utils.h"
 
 #include <windows.h>
 
 #include "webrtc/rtc_base/checks.h"
+#include "webrtc/rtc_base/win32.h"
 
 namespace webrtc {
 
 bool GetScreenList(DesktopCapturer::SourceList* screens) {
   RTC_DCHECK(screens->size() == 0);
 
   BOOL enum_result = TRUE;
   for (int device_index = 0;; ++device_index) {
     DISPLAY_DEVICE device;
     device.cb = sizeof(device);
     enum_result = EnumDisplayDevices(NULL, device_index, &device, 0);
 
     // |enum_result| is 0 if we have enumerated all devices.
     if (!enum_result)
       break;
 
     // We only care about active displays.
     if (!(device.StateFlags & DISPLAY_DEVICE_ACTIVE))
       continue;
 
-    screens->push_back({device_index, std::string()});
+    screens->push_back({device_index, rtc::ToUtf8(device.DeviceName)});

[Do not use (sergeyu), 2017/07/11 18:21:09]

title field is normally used for the title strings that can be shown to the
user. Does DeviceName contain a human-readable string?

[Hzj_jie, 2017/07/11 19:09:25]

The string is in format of \\.\Display{id}. But for screens, this field is not
used anyway.
(https://cs.chromium.org/chromium/src/chrome/browser/media/webrtc/native_deskt...)

[Sergey Ulanov, 2017/07/11 21:34:22]

Even if this field is not used right now it's still better to avoid reusing it
for anything that's not supposed to be shown to the user. Maybe add another
field in Source struct?

[Hzj_jie, 2017/07/11 21:48:32]

Done.

   }
   return true;
 }
 
 bool IsScreenValid(DesktopCapturer::SourceId screen, std::wstring* device_key) {
   if (screen == kFullDesktopScreenId) {
     *device_key = L"";
     return true;
   }
 
@@ skipping 36 matching lines @@
   if (!result)
     return DesktopRect();
 
   return DesktopRect::MakeXYWH(device_mode.dmPosition.x,
                                device_mode.dmPosition.y,
                                device_mode.dmPelsWidth,
                                device_mode.dmPelsHeight);
 }
 
 }  // namespace webrtc