Add missing include

Bug: webrtc:14009
Change-Id: I2d061266417b28d345e6bd88018380b01051952a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/291113
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Cr-Commit-Position: refs/heads/main@{#39204}
diff --git a/modules/desktop_capture/win/full_screen_win_application_handler.cc b/modules/desktop_capture/win/full_screen_win_application_handler.cc
index f7047db..4222dfc 100644
--- a/modules/desktop_capture/win/full_screen_win_application_handler.cc
+++ b/modules/desktop_capture/win/full_screen_win_application_handler.cc
@@ -11,6 +11,7 @@
 #include "modules/desktop_capture/win/full_screen_win_application_handler.h"
 
 #include <algorithm>
+#include <cwctype>
 #include <memory>
 #include <string>
 #include <vector>