Include empty text item after forced break into the line

When |NGLineBreaker| finds a forced break, it includes following close-tags but not empty text items. This caused an additional empty line when there are spaces before/after the close-tags, which causes the `widows` property to count the empty lines. This patch changes |NGLineBreaker| to include them as well. Bug: 1156773 Change-Id: Id01966dd57dce3185d384544e9af662fd43917c2 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2584431Reviewed-by: Morten Stenshorne <mstensho@chromium.org> Commit-Queue: Koji Ishii <kojii@chromium.org> Cr-Commit-Position: refs/heads/master@{#836547}

Include empty text item after forced break into the line
When |NGLineBreaker| finds a forced break, it includes following close-tags but not empty text items. This caused an additional empty line when there are spaces before/after the close-tags, which causes the `widows` property to count the empty lines. This patch changes |NGLineBreaker| to include them as well. Bug: 1156773 Change-Id: Id01966dd57dce3185d384544e9af662fd43917c2 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2584431Reviewed-by: Morten Stenshorne <mstensho@chromium.org> Commit-Queue: Koji Ishii <kojii@chromium.org> Cr-Commit-Position: refs/heads/master@{#836547}
e874837d · Koji Ishii · Chromium LUCI CQ · 243bbb6b · e874837d · e874837d
Commit e874837d authored Dec 14, 2020 by Koji Ishii Committed by Chromium LUCI CQ Dec 14, 2020
3 changed files
--- a/third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker.cc
+++ b/third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker.cc
@@ -1421,6 +1421,10 @@ void NGLineBreaker::HandleControlItem(const NGInlineItem& item,
        HandleCloseTag(next_item, line_info);
        continue;
      }
+      if (next_item.Type() == NGInlineItem::kText && !next_item.Length()) {
+        HandleEmptyText(next_item, line_info);
+        continue;
+      }
      break;
    }

--- a/third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker_test.cc
+++ b/third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker_test.cc
@@ -605,6 +605,38 @@ TEST_F(NGLineBreakerTest, SplitTextZero) {
  EXPECT_EQ("ab", lines[1].first);
 }
+TEST_F(NGLineBreakerTest, ForcedBreakFollowedByCloseTag) {
+  SetBodyInnerHTML(R"HTML(
+    <!DOCTYPE html>
+    <div id="container">
+      <div><span>line<br></span></div>
+      <div>
+        <span>line<br></span>
+      </div>
+      <div>
+        <span>
+          line<br>
+        </span>
+      </div>
+      <div>
+        <span>line<br>  </span>
+      </div>
+      <div>
+        <span>line<br>  </span>&#32;&#32;
+      </div>
+    </div>
+  )HTML");
+  const LayoutObject* container = GetLayoutObjectByElementId("container");
+  for (const LayoutObject* child = container->SlowFirstChild(); child;
+       child = child->NextSibling()) {
+    NGInlineCursor cursor(*To<LayoutBlockFlow>(child));
+    wtf_size_t line_count = 0;
+    for (cursor.MoveToFirstLine(); cursor; cursor.MoveToNextLine())
+      ++line_count;
+    EXPECT_EQ(line_count, 1u);
+  }
+}
 TEST_F(NGLineBreakerTest, TableCellWidthCalculationQuirkOutOfFlow) {
  NGInlineNode node = CreateInlineNode(R"HTML(
    <style>

--- a/third_party/blink/web_tests/TestExpectations
+++ b/third_party/blink/web_tests/TestExpectations
@@ -1095,7 +1095,6 @@ crbug.com/1079031 virtual/layout_ng_block_frag/fast/multicol/tall-line-in-short-
 crbug.com/1079031 virtual/layout_ng_block_frag/fast/multicol/transform-with-fixedpos.html [ Failure ]
 crbug.com/1058792 virtual/layout_ng_block_frag/fast/multicol/vertical-lr/composited-relpos-overlapping-will-change.html [ Failure ]
 crbug.com/1058792 virtual/layout_ng_block_frag/fast/multicol/vertical-rl/composited-relpos-overlapping-will-change.html [ Failure ]
-crbug.com/829028 virtual/layout_ng_block_frag/fast/multicol/widows.html [ Failure ]
 crbug.com/1079031 virtual/layout_ng_block_frag/fragmentation/content-preceding-first-fragmentainer.html [ Crash Failure ]
 crbug.com/1079031 virtual/layout_ng_block_frag/fragmentation/relayout-abspos.html [ Failure ]