Bug 1153478 part 2 - Remove useless assertions. r=roc

layout/generic/nsContainerFrame.cpp

@@ -1620,7 +1620,6 @@ nsContainerFrame::DrainSelfOverflowList()
 {
   AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
   if (overflowFrames) {
-    NS_ASSERTION(mFrames.NotEmpty(), "overflow list w/o frames");
     mFrames.AppendFrames(nullptr, *overflowFrames);
     return true;
   }

layout/generic/nsInlineFrame.cpp

@@ -508,7 +508,6 @@ nsInlineFrame::DrainSelfOverflowListInternal(DrainFlags aFlags,
 {
   AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
   if (overflowFrames) {
-    NS_ASSERTION(mFrames.NotEmpty(), "overflow list w/o frames");
     // The frames on our own overflowlist may have been pushed by a
     // previous lazilySetParentPointer Reflow so we need to ensure the
     // correct parent pointer.  This is sometimes skipped by Reflow.
@@ -1200,8 +1199,6 @@ nsFirstLineFrame::DrainSelfOverflowList()
 {
   AutoFrameListPtr overflowFrames(PresContext(), StealOverflowFrames());
   if (overflowFrames) {
-    NS_ASSERTION(mFrames.NotEmpty(), "overflow list w/o frames");
-
     bool result = !overflowFrames->IsEmpty();
     const nsFrameList::Slice& newFrames =
       mFrames.AppendFrames(nullptr, *overflowFrames);