Support text-indent in layout-2020

Existing WPT now passing:
  - _mozilla/css/text_indent_a.html
  - css/CSS2/css1/c71-fwd-parsing-002.xht
  - css/CSS2/css1/c71-fwd-parsing-004.xht
  - css/CSS2/floats-clear/floats-138.xht
  - css/CSS2/text/text-indent-007.xht
  - css/CSS2/text/text-indent-008.xht
  - css/CSS2/text/text-indent-010.xht
  - css/CSS2/text/text-indent-019.xht
  - css/CSS2/text/text-indent-020.xht
  - css/CSS2/text/text-indent-031.xht
  - css/CSS2/text/text-indent-032.xht
  - css/CSS2/text/text-indent-043.xht
  - css/CSS2/text/text-indent-044.xht
  - css/CSS2/text/text-indent-055.xht
  - css/CSS2/text/text-indent-056.xht
  - css/CSS2/text/text-indent-067.xht
  - css/CSS2/text/text-indent-068.xht
  - css/CSS2/text/text-indent-079.xht
  - css/CSS2/text/text-indent-080.xht
  - css/CSS2/text/text-indent-091.xht
  - css/CSS2/text/text-indent-092.xht
  - css/CSS2/text/text-indent-103.xht
  - css/CSS2/text/text-indent-104.xht
  - css/CSS2/text/text-indent-112.xht
  - css/CSS2/text/text-indent-113.xht
  - css/CSS2/text/text-indent-115.xht
  - css/CSS2/text/text-indent-applies-to-002.xht
  - css/CSS2/text/text-indent-applies-to-003.xht
  - css/CSS2/text/text-indent-applies-to-005.xht
  - css/CSS2/text/text-indent-applies-to-006.xht
  - css/CSS2/text/text-indent-applies-to-007.xht
  - css/CSS2/text/text-indent-applies-to-008.xht
  - css/CSS2/text/text-indent-applies-to-009.xht
  - css/CSS2/text/text-indent-applies-to-010.xht
  - css/CSS2/text/text-indent-applies-to-011.xht
  - css/CSS2/text/text-indent-applies-to-014.xht
  - css/CSS2/text/text-indent-applies-to-015.xht
  - css/CSS2/text/text-indent-inherited-001.xht
  - css/CSS2/text/text-indent-overflow-001.xht
  - css/CSS2/text/text-indent-overflow-002.xht
  - css/CSS2/text/text-indent-overflow-003.xht
  - css/CSS2/text/text-indent-overflow-004.xht
  - css/CSS2/text/text-indent-wrap-001.xht
  - css/css-text-decor/text-shadow/textindent.html
  - css/css-text/text-indent/text-indent-percentage-001.xht
  - css/css-text/text-indent/text-indent-percentage-002.html
  - css/css-text/text-indent/text-indent-percentage-003.html
  - css/css-text/text-indent/text-indent-percentage-004.html
  - css/css-values/minmax-length-percent-serialize.html
  - css/css-values/minmax-length-serialize.html

Also improvements in:
  - _mozilla/mozilla/calc.html
  - css/css-text/animations/text-indent-interpolation.html
  - css/css-text/inheritance.html
  - css/css-text/parsing/text-indent-computed.html
  - css/css-text/parsing/text-indent-valid.html
  - css/css-transitions/properties-value-implicit-001.html
  - css/css-values/animations/calc-interpolation.html
  - css/css-values/minmax-percentage-serialize.html
  - css/css-values/viewport-units-css2-001.html
  - css/css-variables/variable-substitution-basic.html
  - css/cssom/serialize-values.html

Existing WPT now failing, due to lack of direction, outside list markers,
flex and grid:
  - css/CSS2/text/text-indent-rtl-001.xht
  - css/CSS2/text/text-indent-rtl-002.xht
  - css/css-pseudo/marker-content-023.html
  - css/css-text/text-indent/anonymous-flex-item-001.html
  - css/css-text/text-indent/anonymous-grid-item-001.html

New WPT tests:
 - css/css-text/text-indent/text-indent-length-001.html
 - css/css-text/text-indent/text-indent-length-002.html
   This one fails in layout-2013.

1 files changed, 7 insertions, 1 deletions

diff --git a/components/layout_2020/flow/construct.rs b/components/layout_2020/flow/construct.rs
index 5cb1fe51e73..0afb9dfe410 100644
--- a/components/layout_2020/flow/construct.rs
+++ b/components/layout_2020/flow/construct.rs
@@ -63,6 +63,7 @@ impl BlockFormattingContext {
         let ifc = InlineFormattingContext {
             inline_level_boxes,
             text_decoration_line,
+            has_first_formatted_line: true,
         };
         let contents = BlockContainer::InlineFormattingContext(ifc);
         let bfc = Self {
@@ -187,7 +188,10 @@ impl BlockContainer {
             context,
             info,
             block_level_boxes: Vec::new(),
-            ongoing_inline_formatting_context: InlineFormattingContext::new(text_decoration_line),
+            ongoing_inline_formatting_context: InlineFormattingContext::new(
+                text_decoration_line,
+                /* has_first_formatted_line = */ true,
+            ),
             ongoing_inline_boxes_stack: Vec::new(),
             anonymous_style: None,
             contains_floats: ContainsFloats::No,
@@ -690,6 +694,8 @@ where
             .is_empty()
         {
             // There should never be an empty inline formatting context.
+            self.ongoing_inline_formatting_context
+                .has_first_formatted_line = false;
             return;
         }