Remove superfluous <list> includes from headers.

Clearly not needed if the headers do not contain "std::list". Do IWYU in
one header to fix the build after.

Bug: 242216
Change-Id: I8dd7e524453790d4a886a0f5994db31d57df99dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3275074
Reviewed-by: Nico Weber <thakis@chromium.org>
Owners-Override: Nico Weber <thakis@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#959520}
NOKEYCHECK=True
GitOrigin-RevId: 53d656aac6e6ff882163a2170da5d76335eeb341
diff --git a/win/src/broker_services.h b/win/src/broker_services.h
index e63b0cb..a848198 100644
--- a/win/src/broker_services.h
+++ b/win/src/broker_services.h
@@ -5,7 +5,6 @@
 #ifndef SANDBOX_WIN_SRC_BROKER_SERVICES_H_
 #define SANDBOX_WIN_SRC_BROKER_SERVICES_H_
 
-#include <list>
 #include <map>
 #include <memory>
 #include <set>