Remove confusing DLOG from SingletonHwnd

ui/gfx/win/singleton_hwnd.cc

Index: ui/gfx/win/singleton_hwnd.cc
diff --git a/ui/gfx/win/singleton_hwnd.cc b/ui/gfx/win/singleton_hwnd.cc
index 486bcf7ae463315678f5f9fe51739aaaef128c98..814218746a88ef1b561ff7048ee809b0afd7d01a 100644
--- a/ui/gfx/win/singleton_hwnd.cc
+++ b/ui/gfx/win/singleton_hwnd.cc
@@ -31,7 +31,6 @@ SingletonHwnd::SingletonHwnd() {
   if (!base::MessageLoopForUI::IsCurrent()) {
     // Creating this window in (e.g.) a renderer inhibits shutdown on
     // Windows. See http://crbug.com/230122 and http://crbug.com/236039.
-    DLOG(ERROR) << "Cannot create windows on non-UI thread!";

[Nico, 2016/08/26 21:21:37]

could this be a CHECK?

[scottmg, 2016/08/26 21:24:00]

No :( happens all the time (currently) in poorly factored code that runs in all
processes semi-accidentally.

Someday, ideally though, yes.

     return;
   }
   WindowImpl::Init(NULL, Rect());