[LayoutNG] Pass the column block offset to NGOutOfFlowLayoutPart

When determining the column block size of a new proxy fragment that
is added directly after a spanning fragment, we need to know the
current column block offset.

Bug: 1079031
Change-Id: Ibc03d753e927da3b02399d27e986132c4f4833e0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2365355
Commit-Queue: Alison Maher <almaher@microsoft.com>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803672}

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

@@ -226,6 +226,16 @@ class CORE_EXPORT NGBoxFragmentBuilder final
   // building now.
   void SetConsumedBlockSize(LayoutUnit size) { consumed_block_size_ = size; }
 
+  // Set how much of the column block-size we've used so far. This will be used
+  // to determine the block-size of any new columns added by descendant
+  // out-of-flow positioned elements.
+  void SetBlockOffsetForAdditionalColumns(LayoutUnit size) {
+    block_offset_for_additional_columns_ = size;
+  }
+  LayoutUnit BlockOffsetForAdditionalColumns() const {
+    return block_offset_for_additional_columns_;
+  }
+
   void SetSequenceNumber(unsigned sequence_number) {
     sequence_number_ = sequence_number;
   }
@@ -542,6 +552,7 @@ class CORE_EXPORT NGBoxFragmentBuilder final
   bool is_math_fraction_ = false;
   bool is_at_block_end_ = false;
   LayoutUnit consumed_block_size_;
+  LayoutUnit block_offset_for_additional_columns_;
   unsigned sequence_number_ = 0;
 
   LayoutUnit minimal_space_shortage_ = LayoutUnit::Max();

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

@@ -294,6 +294,8 @@ scoped_refptr<const NGLayoutResult> NGColumnLayoutAlgorithm::Layout() {
   container_builder_.SetFragmentsTotalBlockSize(previously_consumed_block_size +
                                                 block_size);
   container_builder_.SetIntrinsicBlockSize(intrinsic_block_size_);
+  container_builder_.SetBlockOffsetForAdditionalColumns(
+      CurrentContentBlockOffset());
 
   if (ConstraintSpace().HasBlockFragmentation()) {
     // In addition to establishing one, we're nested inside another

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

@@ -1152,9 +1152,10 @@ const NGConstraintSpace& NGOutOfFlowLayoutPart::GetFragmentainerConstraintSpace(
       original_column_block_size_ != kIndefiniteSize &&
       !container_builder_->Children()[index + 1]
            .fragment->IsFragmentainerBox()) {
-    // TODO(almaher): Should we take the consumed column block size into
-    // account?
-    column_size.block_size = original_column_block_size_;
+    column_size.block_size =
+        original_column_block_size_ -
+        container_builder_->BlockOffsetForAdditionalColumns();
+    column_size.block_size = column_size.block_size.ClampNegativeToZero();
   }
 
   // TODO(bebeaudr): Need to handle different fragmentation types. It won't
@@ -1227,9 +1228,10 @@ void NGOutOfFlowLayoutPart::ComputeStartFragmentIndexAndRelativeOffset(
   if (original_column_block_size_ != kIndefiniteSize &&
       !container_builder_->Children()[child_index - 1]
            .fragment->IsFragmentainerBox()) {
-    // TODO(almaher): Should we take the consumed column block size into
-    // account?
-    fragmentainer_block_size = original_column_block_size_;
+    fragmentainer_block_size =
+        original_column_block_size_ -
+        container_builder_->BlockOffsetForAdditionalColumns();
+    fragmentainer_block_size = fragmentainer_block_size.ClampNegativeToZero();
   }
 
   wtf_size_t additional_fragment_count =

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

@@ -966,6 +966,8 @@ TEST_F(NGOutOfFlowLayoutPartTest,
 
   // TODO(1079031): With top set to 0px, the abspos should start in the first
   // column with an offset of (0,0).
+  // TODO(1079031): The offsets of the columns following the spanner are
+  // incorrect. (The first should start at (0,10)).
   String expectation = R"DUMP(.:: LayoutNG Physical Fragment Tree ::.
   offset:unplaced size:1000x40
     offset:0,0 size:1000x40
@@ -979,12 +981,69 @@ TEST_F(NGOutOfFlowLayoutPartTest,
       offset:0,10 size:1000x0
       offset:0,10 size:1000x0
       offset:0,10 size:1000x0
-      offset:1016,0 size:492x40
-        offset:0,0 size:5x40
-      offset:1524,0 size:492x40
-        offset:0,0 size:5x40
-      offset:2032,0 size:492x40
+      offset:1016,0 size:492x30
+        offset:0,0 size:5x30
+      offset:1524,0 size:492x30
+        offset:0,0 size:5x30
+      offset:2032,0 size:492x30
+        offset:0,0 size:5x30
+      offset:2540,0 size:492x30
+        offset:0,0 size:5x20
+)DUMP";
+  EXPECT_EQ(expectation, dump);
+}
+
+// Tests that new column fragments are added correctly if a positioned node
+// fragments beyond the last fragmentainer in a context directly after a
+// spanner.
+TEST_F(NGOutOfFlowLayoutPartTest,
+       PositionedFragmentationWithNewColumnsAfterSpanner) {
+  SetBodyInnerHTML(
+      R"HTML(
+      <style>
+        #multicol {
+          column-count:2; column-fill:auto; column-gap:16px; height:40px;
+        }
+        .rel {
+          position: relative; width:30px;
+        }
+        .abs {
+          position:absolute; width:5px; height:50px; top:25px;
+        }
+        .content { height:20px; }
+      </style>
+      <div id="container">
+        <div id="multicol">
+          <div class="rel">
+            <div class="content"></div>
+            <div class="abs"></div>
+          </div>
+          <div style="column-span:all;"></div>
+        </div>
+      </div>
+      )HTML");
+  String dump = DumpFragmentTree(GetElementById("container"));
+
+  // TODO(1079031): With top set to 25px, the abspos should start in the third
+  // column with an offset of (0,5).
+  // TODO(1079031): The offsets of the columns following the spanner are
+  // incorrect. (The first should start at (0,10)).
+  String expectation = R"DUMP(.:: LayoutNG Physical Fragment Tree ::.
+  offset:unplaced size:1000x40
+    offset:0,0 size:1000x40
+      offset:0,0 size:492x10
+        offset:0,0 size:30x10
+          offset:0,0 size:30x10
+      offset:508,0 size:492x10
+        offset:0,0 size:30x10
+          offset:0,0 size:30x10
+      offset:0,10 size:1000x0
+      offset:1016,0 size:492x30
+        offset:0,15 size:5x15
+      offset:1524,0 size:492x30
         offset:0,0 size:5x30
+      offset:2032,0 size:492x30
+        offset:0,0 size:5x5
 )DUMP";
   EXPECT_EQ(expectation, dump);
 }