Remove DCHECK when handle stuffing fails.

sandbox/win/src/handle_closer_agent.cc

Index: sandbox/win/src/handle_closer_agent.cc
diff --git a/sandbox/win/src/handle_closer_agent.cc b/sandbox/win/src/handle_closer_agent.cc
index c18fef4e3707a8616fc2d642eafc6410b672a88b..69a33ecfadcab04974cbda56b963cbe93b2c5062 100644
--- a/sandbox/win/src/handle_closer_agent.cc
+++ b/sandbox/win/src/handle_closer_agent.cc
@@ -85,9 +85,8 @@ bool HandleCloserAgent::AttemptToStuffHandleSlot(HANDLE closed_handle,
   for (HANDLE h : to_close)
     ::CloseHandle(h);
 
-  // Useful to know when we're not able to stuff handles.
-  DCHECK(dup_dummy == closed_handle);
-
+  // TODO(wfh): Investigate why stuffing handles sometimes fails.
+  // http://crbug.com/649904
   return dup_dummy == closed_handle;
 }