Do not assume /DUNICODE and /D_UNICODE.

As a library, WebRTC should not assume UNICODE and _UNICODE to be
defined globally.

This CL explicitly selects wide character functions and types in
order to build WebRTC with /UUNICODE and /U_UNICODE.

Bug: None
Change-Id: Ie4e2bcb4c5c34aee6f68dc7b5b54b76f088ee3e4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128904
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Noah Richards <noahric@chromium.org>
Cr-Commit-Position: refs/heads/master@{#27313}
diff --git a/rtc_base/win32_socket_server.h b/rtc_base/win32_socket_server.h
index 37515d9..5c209d9 100644
--- a/rtc_base/win32_socket_server.h
+++ b/rtc_base/win32_socket_server.h
@@ -121,7 +121,7 @@
     Win32SocketServer* ss_;
   };
 
-  static const TCHAR kWindowName[];
+  static const wchar_t kWindowName[];
   MessageQueue* message_queue_;
   MessageWindow wnd_;
   CriticalSection cs_;