[layoutng] Use Shrink(0) rather than resize(0)

This allows me to remove the otherwise-unnecessary constructors
I added in https://chromium-review.googlesource.com/c/chromium/src/+/1286884

R=eae@chromium.org

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I720e6a128b6aa16db734bbc4bad94c0af827782d
Reviewed-on: https://chromium-review.googlesource.com/c/1289304Reviewed-by: Aleks Totic <atotic@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600894}

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

@@ -725,8 +725,8 @@ scoped_refptr<NGLayoutResult> NGInlineLayoutAlgorithm::Layout() {
 #endif
 
     // Reset any state that may have been modified in a previous pass.
-    positioned_floats.resize(0);
-    unpositioned_floats_.resize(0);
+    positioned_floats.Shrink(0);
+    unpositioned_floats_.Shrink(0);
     container_builder_.Reset();
     exclusion_space = initial_exclusion_space;
 
@@ -876,7 +876,7 @@ void NGInlineLayoutAlgorithm::PositionPendingFloats(
       << "The floats BFC block offset should be known here";
 
   if (BreakToken() && BreakToken()->IgnoreFloats()) {
-    unpositioned_floats_.resize(0);
+    unpositioned_floats_.Shrink(0);
     return;
   }
 
@@ -896,7 +896,7 @@ void NGInlineLayoutAlgorithm::PositionPendingFloats(
                  ConstraintSpace(), exclusion_space, &positioned_floats);
 
   positioned_floats_.AppendVector(positioned_floats);
-  unpositioned_floats_.resize(0);
+  unpositioned_floats_.Shrink(0);
 }
 
 void NGInlineLayoutAlgorithm::BidiReorder() {

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

@@ -733,7 +733,7 @@ static LayoutUnit ComputeContentSize(
       nullptr /* container_builder */, &empty_exclusion_space, 0u,
       line_opportunity, nullptr /* break_token */);
   do {
-    unpositioned_floats.resize(0);
+    unpositioned_floats.Shrink(0);
 
     NGLineInfo line_info;
     line_breaker.NextLine(&line_info);

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

@@ -2089,7 +2089,7 @@ void NGBlockLayoutAlgorithm::PositionPendingFloats(
 
   AddPositionedFloats(positioned_floats);
 
-  unpositioned_floats_.resize(0);
+  unpositioned_floats_.Shrink(0);
 }
 
 template <class Vec>

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

@@ -171,7 +171,7 @@ void NGContainerFragmentBuilder::GetAndClearOutOfFlowDescendantCandidates(
   // The descendant may be a "position: absolute" which contains a "position:
   // fixed" for example. (This fragment isn't the containing block for the
   // fixed descendant).
-  oof_positioned_candidates_.resize(0);
+  oof_positioned_candidates_.Shrink(0);
 }
 
 void NGContainerFragmentBuilder::MoveOutOfFlowDescendantCandidatesToDescendants(

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

@@ -206,10 +206,6 @@ class CORE_EXPORT NGContainerFragmentBuilder : public NGBaseFragmentBuilder {
           child_offset(child_offset_arg),
           is_line_relative(true),
           line_direction(line_direction_arg) {}
-
-    // This constructor is not meant to be called, but required so we can use
-    // Vector::resize(0).
-    NGOutOfFlowPositionedCandidate() {}
   };
 
   NGContainerFragmentBuilder(scoped_refptr<const ComputedStyle>,

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

@@ -74,7 +74,7 @@ void NGOutOfFlowLayoutPart::Run(LayoutBox* only_layout) {
     }
     // Sweep any descendants that might have been added.
     // This happens when an absolute container has a fixed child.
-    descendant_candidates.resize(0);
+    descendant_candidates.Shrink(0);
     container_builder_->GetAndClearOutOfFlowDescendantCandidates(
         &descendant_candidates, container_builder_->GetLayoutObject());
   }

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

@@ -33,10 +33,6 @@ struct CORE_EXPORT NGOutOfFlowPositionedDescendant {
       : node(node_param),
         static_position(static_position_param),
         inline_container(inline_container_param) {}
-
-  // This constructor is not meant to be called, but required so we can use
-  // Vector::resize(0).
-  NGOutOfFlowPositionedDescendant() : node(nullptr) {}
 };
 
 }  // namespace blink

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

@@ -15,10 +15,6 @@ class NGLayoutResult;
 
 // Contains the information necessary for copying back data to a FloatingObject.
 struct CORE_EXPORT NGPositionedFloat {
-  // This constructor is not meant to be called, but required so we can use
-  // Vector::resize(0).
-  NGPositionedFloat() {}
-
   NGPositionedFloat(scoped_refptr<NGLayoutResult> layout_result,
                     const NGBfcOffset& bfc_offset);
   ~NGPositionedFloat();

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

@@ -20,10 +20,6 @@ struct CORE_EXPORT NGUnpositionedFloat final {
   DISALLOW_NEW();
 
  public:
-  // This constructor is not meant to be called, but required so we can use
-  // Vector::resize(0).
-  NGUnpositionedFloat() : node(nullptr) {}
-
   NGUnpositionedFloat(NGBlockNode node, const NGBlockBreakToken* token)
       : node(node), token(token) {}