Fixed the racy code around the message-only window in base::MessagePumpForUI on Windows.

tools/valgrind/tsan/suppressions.txt

Index: tools/valgrind/tsan/suppressions.txt
diff --git a/tools/valgrind/tsan/suppressions.txt b/tools/valgrind/tsan/suppressions.txt
index a771a4851183415b7f8786a31577090918be1eba..26501006af71d91002eae21cd7a82d77b2f24562 100644
--- a/tools/valgrind/tsan/suppressions.txt
+++ b/tools/valgrind/tsan/suppressions.txt
@@ -1126,34 +1126,3 @@
   ...
   fun:media::FFmpegVideoDecoder::Decode
 }
-{
-  bug_241939a
-  ThreadSanitizer:Race
-  fun:CreateDialogParamW
-  fun:CharPrevW
-  fun:SystemParametersInfoW
-  fun:RegisterClassExW
-  fun:base::MessagePumpForUI::InitMessageWnd
-  fun:base::MessagePumpForUI::MessagePumpForUI
-  fun:base::MessageLoop::MessageLoop
-  fun:remoting::AutoThread::ThreadMain
-}
-{
-  bug_241939b
-  ThreadSanitizer:Race
-  fun:GetWindowLongW
-  fun:GetWindowLongW
-  fun:GetWindowLongW
-  fun:PostMessageW
-  fun:PostMessageW
-  fun:SetWindowTextW
-  fun:KiUserCallbackDispatcher
-  fun:LoadStringA
-  fun:LoadStringA
-  fun:LoadStringA
-  fun:CreateWindowExW
-  fun:base::MessagePumpForUI::InitMessageWnd
-  fun:base::MessagePumpForUI::MessagePumpForUI
-  fun:base::MessageLoop::MessageLoop
-  fun:remoting::AutoThread::ThreadMain
-}