Bug 959391 - Remove hard to debug assert. r=jdm

netwerk/ipc/NeckoCommon.h

@@ -123,12 +123,6 @@ MissingRequiredTabChild(mozilla::dom::TabChild* tabChild,
                         const char* context)
 {
   if (UsingNeckoIPCSecurity()) {
-    // Bug 833935: during navigation away from page some loads may lack
-    // TabParent: we don't want to kill browser for that.  Doesn't happen in
-    // test harness, so fail in debug mode so we can catch new code that fails
-    // to pass security info.
-    MOZ_ASSERT(tabChild);
-
     if (!tabChild) {
       printf_stderr("WARNING: child tried to open %s IPDL channel w/o "
                     "security info\n", context);