[LayoutNG] Remove unreachable if-stmt in float utils.

This if-stmt is now invalid as inside the NGExclusionSpace there is
always at least one opportunity which has a block-end offset of
LayoutUnit::Max().

Bug: 635619
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I4ca866e38b4aa764b3181c59e642e2a5be422a55
Reviewed-on: https://chromium-review.googlesource.com/1028351Reviewed-by: Aleks Totic <atotic@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553780}

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

@@ -222,18 +222,6 @@ NGPositionedFloat PositionFloat(LayoutUnit origin_block_offset,
   NGFragment float_fragment(parent_space.GetWritingMode(),
                             *layout_result->PhysicalFragment());
 
-  // TODO(glebl): This should check for infinite opportunity instead.
-  // TODO(ikilpatrick): Remove.
-  if (opportunity.rect.IsEmpty()) {
-    // Because of the implementation specific of the layout opportunity iterator
-    // an empty opportunity can mean 2 things:
-    // - search for layout opportunities is exhausted.
-    // - opportunity has an infinite size. That's because CS is infinite.
-    opportunity = NGLayoutOpportunity(NGBfcRect(
-        /* start_offset */ NGBfcOffset(), /* end_offset */ NGBfcOffset(
-            float_fragment.InlineSize(), float_fragment.BlockSize())));
-  }
-
   LayoutUnit float_margin_box_inline_size =
       float_fragment.InlineSize() + unpositioned_float->margins.InlineSum();