[layoutng] Give the positioned floats vector an inline capacity

For the cases where we store that vector on the stack, we can
easily give it an inline capacity and gain some performance.

There is one function that can take either a stack-based or
LayoutResult-based positioned floats vector; I made that a template
so it can accept either one.

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I2afb67e03862f062864dd4d36c740b5c578041aa
Reviewed-on: https://chromium-review.googlesource.com/1226159Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593686}

third_party/blink/renderer/core/layout/ng/inline/ng_inline_layout_algorithm.cc

@@ -853,7 +853,7 @@ void NGInlineLayoutAlgorithm::PositionPendingFloats(
   NGBfcOffset origin_bfc_offset = {ConstraintSpace().BfcOffset().line_offset,
                                    bfc_block_offset + content_size};
 
-  const Vector<NGPositionedFloat> positioned_floats =
+  const NGPositionedFloatVector positioned_floats =
       PositionFloats(ConstraintSpace().AvailableSize(),
                      ConstraintSpace().PercentageResolutionSize(),
                      ConstraintSpace().ReplacedPercentageResolutionSize(),

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

@@ -2074,8 +2074,8 @@ void NGBlockLayoutAlgorithm::PositionPendingFloats(
   unpositioned_floats_.clear();
 }
 
-void NGBlockLayoutAlgorithm::AddPositionedFloats(
-    const Vector<NGPositionedFloat>& positioned_floats) {
+template <class Vec>
+void NGBlockLayoutAlgorithm::AddPositionedFloats(const Vec& positioned_floats) {
   DCHECK(container_builder_.BfcBlockOffset() ||
          ConstraintSpace().FloatsBfcBlockOffset())
       << "The parent BFC block offset should be known here";

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

@@ -11,6 +11,7 @@
 #include "third_party/blink/renderer/core/layout/ng/geometry/ng_margin_strut.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_block_break_token.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_block_node.h"
+#include "third_party/blink/renderer/core/layout/ng/ng_floats_utils.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_fragment_builder.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_layout_algorithm.h"
 #include "third_party/blink/renderer/core/layout/ng/ng_unpositioned_float.h"
@@ -244,7 +245,8 @@ class CORE_EXPORT NGBlockLayoutAlgorithm
   void PositionPendingFloats(LayoutUnit origin_block_offset);
 
   // Adds a set of positioned floats as children to the current fragment.
-  void AddPositionedFloats(const Vector<NGPositionedFloat>& positioned_floats);
+  template <class Vec>
+  void AddPositionedFloats(const Vec& positioned_floats);
 
   // Positions a list marker for the specified block content.
   void PositionOrPropagateListMarker(const NGLayoutResult&, NGLogicalOffset*);

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

@@ -306,7 +306,7 @@ NGPositionedFloat PositionFloat(
   return NGPositionedFloat(std::move(layout_result), float_bfc_offset);
 }
 
-const Vector<NGPositionedFloat> PositionFloats(
+const NGPositionedFloatVector PositionFloats(
     const NGLogicalSize& float_available_size,
     const NGLogicalSize& float_percentage_size,
     const NGLogicalSize& float_replaced_percentage_size,
@@ -315,7 +315,7 @@ const Vector<NGPositionedFloat> PositionFloats(
     NGUnpositionedFloatVector& unpositioned_floats,
     const NGConstraintSpace& space,
     NGExclusionSpace* exclusion_space) {
-  Vector<NGPositionedFloat> positioned_floats;
+  NGPositionedFloatVector positioned_floats;
   positioned_floats.ReserveCapacity(unpositioned_floats.size());
 
   for (NGUnpositionedFloat& unpositioned_float : unpositioned_floats) {

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

@@ -23,6 +23,8 @@ struct NGLogicalSize;
 struct NGPositionedFloat;
 struct NGUnpositionedFloat;
 
+typedef Vector<NGPositionedFloat, 8> NGPositionedFloatVector;
+
 enum NGFloatTypeValue {
   kFloatTypeNone = 0b00,
   kFloatTypeLeft = 0b01,
@@ -51,15 +53,15 @@ PositionFloat(const NGLogicalSize& float_available_size,
 
 // Positions the list of {@code unpositioned_floats}. Adds them as exclusions to
 // {@code space}.
-CORE_EXPORT const Vector<NGPositionedFloat> PositionFloats(
-    const NGLogicalSize& float_available_size,
-    const NGLogicalSize& float_percentage_size,
-    const NGLogicalSize& float_replaced_percentage_size,
-    const NGBfcOffset& origin_bfc_offset,
-    LayoutUnit container_block_offset,
-    NGUnpositionedFloatVector& unpositioned_floats,
-    const NGConstraintSpace& space,
-    NGExclusionSpace* exclusion_space);
+CORE_EXPORT const NGPositionedFloatVector
+PositionFloats(const NGLogicalSize& float_available_size,
+               const NGLogicalSize& float_percentage_size,
+               const NGLogicalSize& float_replaced_percentage_size,
+               const NGBfcOffset& origin_bfc_offset,
+               LayoutUnit container_block_offset,
+               NGUnpositionedFloatVector& unpositioned_floats,
+               const NGConstraintSpace& space,
+               NGExclusionSpace* exclusion_space);
 
 // Add a pending float to the list. It will be committed (positioned) once we
 // have resolved the BFC block offset.