[LayoutNG] Remove PositionWithBfcOffset().

There's no need to position pending floats at this point, since there
should be none. Added a DCHECK. If a child knows its BFC offset, it has
no reason to leave behind pending floats.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I288b0cbd0ce43e422eddfe331dc02a5ee3afd6a8
Reviewed-on: https://chromium-review.googlesource.com/1013486Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551028}

third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.cc

@@ -967,10 +967,13 @@ bool NGBlockLayoutAlgorithm::HandleInflow(
   // We try and position the child within the block formatting context. This
   // may cause our BFC offset to be resolved, in which case we should abort our
   // layout if needed.
-  WTF::Optional<NGBfcOffset> child_bfc_offset;
-  if (layout_result->BfcOffset()) {
-    if (!PositionWithBfcOffset(layout_result->BfcOffset().value(),
-                               &child_bfc_offset))
+  WTF::Optional<NGBfcOffset> child_bfc_offset = layout_result->BfcOffset();
+  if (child_bfc_offset) {
+    // A child with a known BFC offset shouldn't leave behind pending floats.
+    DCHECK(unpositioned_floats_.IsEmpty());
+
+    bool updated = MaybeUpdateFragmentBfcOffset(child_bfc_offset->block_offset);
+    if (updated && abort_when_bfc_resolved_)
       return false;
   } else {
     // Layout wasn't able to determine the BFC offset of the child. This has to
@@ -1190,21 +1193,6 @@ NGPreviousInflowPosition NGBlockLayoutAlgorithm::ComputeInflowPosition(
           empty_or_sibling_empty_affected_by_clearance};
 }
 
-bool NGBlockLayoutAlgorithm::PositionWithBfcOffset(
-    const NGBfcOffset& bfc_offset,
-    WTF::Optional<NGBfcOffset>* child_bfc_offset) {
-  LayoutUnit bfc_block_offset = bfc_offset.block_offset;
-  bool updated = MaybeUpdateFragmentBfcOffset(bfc_block_offset);
-
-  if (updated && abort_when_bfc_resolved_)
-    return false;
-
-  PositionPendingFloats(bfc_block_offset);
-
-  *child_bfc_offset = bfc_offset;
-  return true;
-}
-
 NGBfcOffset NGBlockLayoutAlgorithm::PositionEmptyChildWithParentBfc(
     const NGLayoutInputNode& child,
     const NGConstraintSpace& child_space,

third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.h

@@ -81,10 +81,6 @@ class CORE_EXPORT NGBlockLayoutAlgorithm
       const NGFragment& fragment,
       bool empty_block_affected_by_clearance);
 
-  // Positions the fragment that knows its BFC offset.
-  bool PositionWithBfcOffset(const NGBfcOffset& bfc_offset,
-                             WTF::Optional<NGBfcOffset>* child_bfc_offset);
-
   // Position an empty child using the parent BFC offset.
   // The fragment doesn't know its offset, but we can still calculate its BFC
   // position because the parent fragment's BFC is known.