[LayoutNG] Float behavior simplification before larger patch.

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
index 45e959ef1f60657a42347f4f22e36371dc2652d5..24d41129938c60d8d57edd39bcdaa93fc16c0488 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
@@ -91,34 +91,23 @@ void MaybeUpdateFragmentBfcOffset(const NGConstraintSpace& space,
   }
 }
 
-void PositionPendingFloatsFromOffset(LayoutUnit origin_block_offset,
-                                     LayoutUnit from_block_offset,
-                                     NGFragmentBuilder* container_builder,
-                                     NGConstraintSpace* space) {
+void PositionPendingFloats(LayoutUnit origin_block_offset,
+                           NGFragmentBuilder* container_builder,
+                           NGConstraintSpace* space) {
   DCHECK(container_builder->BfcOffset())
       << "Parent BFC offset should be known here";
+
   const auto& unpositioned_floats = container_builder->UnpositionedFloats();
-  const auto positioned_floats =
-      PositionFloats(origin_block_offset, from_block_offset,
-                     container_builder->BfcOffset().value().block_offset,
-                     unpositioned_floats, space);
+  const auto positioned_floats = PositionFloats(
+      origin_block_offset, container_builder->BfcOffset().value().block_offset,
+      unpositioned_floats, space);
+
   for (const auto& positioned_float : positioned_floats)
     container_builder->AddPositionedFloat(positioned_float);
 
   container_builder->MutableUnpositionedFloats().clear();

[eae, 2017/06/29 22:21:18]

Exposing the mutable list like this is a little weird. How about having the
UnpositionedFloats method use move semantics to transfer ownership of the list?

That way this code would take ownership of the unpositioned floats and the clear
method will no longer be needed.

[ikilpatrick, 2017/06/29 22:34:42]

So this will actually go away in the larger patch, as both the block&inline
layout algorithms will have their own list of unpositioned_floats now...
removing this now would be a larger change :).

 }
 
-void PositionPendingFloats(LayoutUnit origin_block_offset,
-                           NGFragmentBuilder* container_builder,
-                           NGConstraintSpace* space) {
-  DCHECK(container_builder->BfcOffset())
-      << "Parent BFC offset should be known here";
-  LayoutUnit from_block_offset =
-      container_builder->BfcOffset().value().block_offset;
-  PositionPendingFloatsFromOffset(origin_block_offset, from_block_offset,
-                                  container_builder, space);
-}
-
 NGBlockLayoutAlgorithm::NGBlockLayoutAlgorithm(NGBlockNode node,
                                                NGConstraintSpace* space,
                                                NGBlockBreakToken* break_token)
@@ -374,11 +363,13 @@ void NGBlockLayoutAlgorithm::HandleFloating(
   // Calculate margins in the BFC's writing mode.
   NGBoxStrut margins = CalculateMargins(child);
 
-  NGLogicalOffset origin_offset = constraint_space_->BfcOffset();
-  origin_offset.inline_offset += border_scrollbar_padding_.inline_start;
+  LayoutUnit origin_inline_offset =
+      constraint_space_->BfcOffset().inline_offset +
+      border_scrollbar_padding_.inline_start;
+
   RefPtr<NGUnpositionedFloat> unpositioned_float = NGUnpositionedFloat::Create(
-      child_available_size_, child_percentage_size_, origin_offset,
-      constraint_space_->BfcOffset(), margins, child, token);
+      child_available_size_, child_percentage_size_, origin_inline_offset,
+      constraint_space_->BfcOffset().inline_offset, margins, child, token);
   container_builder_.AddUnpositionedFloat(unpositioned_float);
 
   // If there is a break token for a float we must be resuming layout, we must
@@ -536,7 +527,6 @@ NGLogicalOffset NGBlockLayoutAlgorithm::PositionNewFc(
           .SetIsNewFormattingContext(false)
           .ToConstraintSpace(child_space.WritingMode());
   PositionFloats(child_bfc_offset_estimate, child_bfc_offset_estimate,
-                 child_bfc_offset_estimate,
                  container_builder_.UnpositionedFloats(), tmp_space.Get());
 
   NGLogicalOffset origin_offset = {ConstraintSpace().BfcOffset().inline_offset +
@@ -610,9 +600,8 @@ NGLogicalOffset NGBlockLayoutAlgorithm::PositionWithParentBfc(
           layout_result.EndMarginStrut().Sum()};
 
   AdjustToClearance(space.ClearanceOffset(), &child_bfc_offset);
-  PositionPendingFloatsFromOffset(
-      child_bfc_offset.block_offset, child_bfc_offset.block_offset,
-      &container_builder_, MutableConstraintSpace());
+  PositionPendingFloats(child_bfc_offset.block_offset, &container_builder_,
+                        MutableConstraintSpace());
   return child_bfc_offset;
 }