diff --git a/Cargo.lock b/Cargo.lock
index e409bd7b6f8..30b04455ca9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3338,6 +3338,7 @@ dependencies = [
  "gfx",
  "gfx_traits",
  "html5ever",
+ "icu_segmenter",
  "ipc-channel",
  "lazy_static",
  "log",
diff --git a/Cargo.toml b/Cargo.toml
index 42e636914ca..d501ee84f61 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -55,6 +55,7 @@ http = "0.2"
 hyper = "0.14"
 hyper-rustls = { version = "0.24", default-features = false, features = ["acceptor", "http1", "http2", "logging", "tls12", "webpki-tokio"] }
 hyper_serde = { path = "components/hyper_serde" }
+icu_segmenter = "1.5.0"
 image = "0.24"
 imsz = "0.2"
 indexmap = { version = "2.2.6", features = ["std"] }
diff --git a/components/layout_2020/Cargo.toml b/components/layout_2020/Cargo.toml
index 5810cfee983..45283da0257 100644
--- a/components/layout_2020/Cargo.toml
+++ b/components/layout_2020/Cargo.toml
@@ -9,7 +9,7 @@ publish = false
 [lib]
 name = "layout_2020"
 path = "lib.rs"
-test = false
+test = true
 doctest = false
 
 [dependencies]
@@ -26,6 +26,7 @@ fxhash = { workspace = true }
 gfx = { path = "../gfx" }
 gfx_traits = { workspace = true }
 html5ever = { workspace = true }
+icu_segmenter = { workspace = true }
 ipc-channel = { workspace = true }
 log = { workspace = true }
 net_traits = { workspace = true }
diff --git a/components/layout_2020/flow/inline/construct.rs b/components/layout_2020/flow/inline/construct.rs
index b88b5014f01..e3f4d8055a0 100644
--- a/components/layout_2020/flow/inline/construct.rs
+++ b/components/layout_2020/flow/inline/construct.rs
@@ -131,8 +131,16 @@ impl InlineFormattingContextBuilder {
             ArcRefCell::new(InlineLevelBox::Atomic(independent_formatting_context));
         self.current_inline_level_boxes()
             .push(inline_level_box.clone());
+
+        // Push an object replacement character for this atomic, which will ensure that the line breaker
+        // inserts a line breaking opportunity here.
+        let string_to_push = "\u{fffc}";
+        self.text_segments.push(string_to_push.to_owned());
+        self.current_text_offset += string_to_push.len();
+
         self.last_inline_box_ended_with_collapsible_white_space = false;
         self.on_word_boundary = true;
+
         inline_level_box
     }
 
diff --git a/components/layout_2020/flow/inline/line_breaker.rs b/components/layout_2020/flow/inline/line_breaker.rs
new file mode 100644
index 00000000000..28301fdadf8
--- /dev/null
+++ b/components/layout_2020/flow/inline/line_breaker.rs
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::ops::Range;
+
+use icu_segmenter::LineSegmenter;
+
+pub(crate) struct LineBreaker {
+    linebreaks: Vec<usize>,
+    current_offset: usize,
+}
+
+impl LineBreaker {
+    pub(crate) fn new(string: &str) -> Self {
+        let line_segmenter = LineSegmenter::new_auto();
+        Self {
+            // From https://docs.rs/icu_segmenter/1.5.0/icu_segmenter/struct.LineSegmenter.html
+            // > For consistency with the grapheme, word, and sentence segmenters, there is always a
+            // > breakpoint returned at index 0, but this breakpoint is not a meaningful line break
+            // > opportunity.
+            //
+            // Skip this first line break opportunity, as it isn't interesting to us.
+            linebreaks: line_segmenter.segment_str(string).skip(1).collect(),
+            current_offset: 0,
+        }
+    }
+
+    pub(crate) fn advance_to_linebreaks_in_range(&mut self, text_range: Range<usize>) -> &[usize] {
+        let linebreaks_in_range = self.linebreaks_in_range_after_current_offset(text_range);
+        self.current_offset = linebreaks_in_range.end;
+        &self.linebreaks[linebreaks_in_range]
+    }
+
+    fn linebreaks_in_range_after_current_offset(&self, text_range: Range<usize>) -> Range<usize> {
+        assert!(text_range.start <= text_range.end);
+
+        let mut linebreaks_range = self.current_offset..self.linebreaks.len();
+
+        while self.linebreaks[linebreaks_range.start] < text_range.start &&
+            linebreaks_range.len() > 1
+        {
+            linebreaks_range.start += 1;
+        }
+
+        let mut ending_linebreak_index = linebreaks_range.start;
+        while self.linebreaks[ending_linebreak_index] < text_range.end &&
+            ending_linebreak_index < self.linebreaks.len() - 1
+        {
+            ending_linebreak_index += 1;
+        }
+        linebreaks_range.end = ending_linebreak_index;
+        linebreaks_range
+    }
+}
+
+#[test]
+fn test_linebreaker_ranges() {
+    let linebreaker = LineBreaker::new("abc def");
+    assert_eq!(linebreaker.linebreaks, [4, 7]);
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(0..5),
+        0..1
+    );
+    // The last linebreak should not be included for the text range we are interested in.
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(0..7),
+        0..1
+    );
+
+    let linebreaker = LineBreaker::new("abc d def");
+    assert_eq!(linebreaker.linebreaks, [4, 6, 9]);
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(0..5),
+        0..1
+    );
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(0..7),
+        0..2
+    );
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(0..9),
+        0..2
+    );
+
+    assert_eq!(
+        linebreaker.linebreaks_in_range_after_current_offset(4..9),
+        0..2
+    );
+
+    std::panic::catch_unwind(|| {
+        let linebreaker = LineBreaker::new("abc def");
+        linebreaker.linebreaks_in_range_after_current_offset(5..2);
+    })
+    .expect_err("Reversed range should cause an assertion failure.");
+}
+
+#[test]
+fn test_linebreaker_stateful_advance() {
+    let mut linebreaker = LineBreaker::new("abc d def");
+    assert_eq!(linebreaker.linebreaks, [4, 6, 9]);
+    assert!(linebreaker.advance_to_linebreaks_in_range(0..7) == &[4, 6]);
+    assert!(linebreaker.advance_to_linebreaks_in_range(8..9).is_empty());
+
+    // We've already advanced, so a range from the beginning shouldn't affect things.
+    assert!(linebreaker.advance_to_linebreaks_in_range(0..9).is_empty());
+
+    linebreaker.current_offset = 0;
+
+    // Sending a value out of range shoudn't break things.
+    assert!(linebreaker.advance_to_linebreaks_in_range(0..999) == &[4, 6]);
+
+    linebreaker.current_offset = 0;
+
+    std::panic::catch_unwind(|| {
+        let mut linebreaker = LineBreaker::new("abc d def");
+        linebreaker.advance_to_linebreaks_in_range(2..0);
+    })
+    .expect_err("Reversed range should cause an assertion failure.");
+}
diff --git a/components/layout_2020/flow/inline/mod.rs b/components/layout_2020/flow/inline/mod.rs
index 4856e86c4bc..773c93a0a97 100644
--- a/components/layout_2020/flow/inline/mod.rs
+++ b/components/layout_2020/flow/inline/mod.rs
@@ -70,6 +70,7 @@
 
 pub mod construct;
 pub mod line;
+mod line_breaker;
 pub mod text_run;
 
 use std::cell::OnceCell;
@@ -84,6 +85,7 @@ use line::{
     layout_line_items, AbsolutelyPositionedLineItem, AtomicLineItem, FloatLineItem,
     InlineBoxLineItem, LineItem, LineItemLayoutState, LineMetrics, TextRunLineItem,
 };
+use line_breaker::LineBreaker;
 use serde::Serialize;
 use servo_arc::Arc;
 use style::computed_values::text_wrap_mode::T as TextWrapMode;
@@ -1593,13 +1595,13 @@ impl InlineFormattingContext {
         let text_content: String = builder.text_segments.into_iter().collect();
         let mut font_metrics = Vec::new();
 
-        let mut linebreaker = None;
+        let mut new_linebreaker = LineBreaker::new(text_content.as_str());
         inline_formatting_context.foreach(|iter_item| match iter_item {
             InlineFormattingContextIterItem::Item(InlineLevelBox::TextRun(ref mut text_run)) => {
-                text_run.break_and_shape(
-                    &text_content[text_run.text_range.clone()],
+                text_run.segment_and_shape(
+                    &text_content,
                     &layout_context.font_context,
-                    &mut linebreaker,
+                    &mut new_linebreaker,
                     &mut font_metrics,
                 );
             },
diff --git a/components/layout_2020/flow/inline/text_run.rs b/components/layout_2020/flow/inline/text_run.rs
index 5ac92e91f16..0b563703f46 100644
--- a/components/layout_2020/flow/inline/text_run.rs
+++ b/components/layout_2020/flow/inline/text_run.rs
@@ -18,13 +18,13 @@ use servo_arc::Arc;
 use style::computed_values::text_rendering::T as TextRendering;
 use style::computed_values::white_space_collapse::T as WhiteSpaceCollapse;
 use style::computed_values::word_break::T as WordBreak;
-use style::properties::style_structs::InheritedText;
 use style::properties::ComputedValues;
 use style::str::char_is_whitespace;
 use style::values::computed::OverflowWrap;
 use unicode_script::Script;
-use xi_unicode::{linebreak_property, LineBreakLeafIter};
+use xi_unicode::linebreak_property;
 
+use super::line_breaker::LineBreaker;
 use super::{FontKeyAndMetrics, InlineFormattingContextState};
 use crate::fragment_tree::BaseFragmentInfo;
 
@@ -84,8 +84,8 @@ pub(crate) struct TextRunSegment {
     #[serde(skip_serializing)]
     pub script: Script,
 
-    /// The range of bytes in the [`TextRun`]'s text that this segment covers.
-    pub range: ServoRange<ByteIndex>,
+    /// The range of bytes in the parent [`super::InlineFormattingContext`]'s text content.
+    pub range: Range<usize>,
 
     /// Whether or not the linebreaker said that we should allow a line break at the start of this
     /// segment.
@@ -96,11 +96,11 @@ pub(crate) struct TextRunSegment {
 }
 
 impl TextRunSegment {
-    fn new(font_index: usize, script: Script, byte_index: ByteIndex) -> Self {
+    fn new(font_index: usize, script: Script, start_offset: usize) -> Self {
         Self {
             script,
             font_index,
-            range: ServoRange::new(byte_index, ByteIndex(0)),
+            range: start_offset..start_offset,
             runs: Vec::new(),
             break_at_start: false,
         }
@@ -167,6 +167,158 @@ impl TextRunSegment {
             );
         }
     }
+
+    fn shape_and_push_range(
+        &mut self,
+        range: &Range<usize>,
+        formatting_context_text: &str,
+        segment_font: &FontRef,
+        options: &ShapingOptions,
+    ) {
+        self.runs.push(GlyphRun {
+            glyph_store: segment_font.shape_text(&formatting_context_text[range.clone()], options),
+            range: ServoRange::new(
+                ByteIndex(range.start as isize),
+                ByteIndex(range.len() as isize),
+            ),
+        });
+    }
+
+    /// Shape the text of this [`TextRunSegment`], first finding "words" for the shaper by processing
+    /// the linebreaks found in the owning [`super::InlineFormattingContext`]. Linebreaks are filtered,
+    /// based on the style of the parent inline box.
+    fn shape_text(
+        &mut self,
+        parent_style: &ComputedValues,
+        formatting_context_text: &str,
+        linebreaker: &mut LineBreaker,
+        shaping_options: &ShapingOptions,
+        font: FontRef,
+    ) {
+        // Gather the linebreaks that apply to this segment from the inline formatting context's collection
+        // of line breaks. Also add a simulated break at the end of the segment in order to ensure the final
+        // piece of text is processed.
+        let range = self.range.clone();
+        let linebreaks = linebreaker.advance_to_linebreaks_in_range(self.range.clone());
+        let linebreak_iter = linebreaks.iter().chain(std::iter::once(&range.end));
+
+        self.runs.clear();
+        self.runs.reserve(linebreaks.len());
+        self.break_at_start = false;
+
+        let text_style = parent_style.get_inherited_text().clone();
+        let can_break_anywhere = text_style.word_break == WordBreak::BreakAll ||
+            text_style.overflow_wrap == OverflowWrap::Anywhere ||
+            text_style.overflow_wrap == OverflowWrap::BreakWord;
+
+        let mut last_slice_end = self.range.start;
+        for break_index in linebreak_iter {
+            if *break_index == self.range.start {
+                self.break_at_start = true;
+                continue;
+            }
+
+            // Extend the slice to the next UAX#14 line break opportunity.
+            let mut slice = last_slice_end..*break_index;
+            let word = &formatting_context_text[slice.clone()];
+
+            // Split off any trailing whitespace into a separate glyph run.
+            let mut whitespace = slice.end..slice.end;
+            let mut rev_char_indices = word.char_indices().rev().peekable();
+            let ends_with_newline = rev_char_indices
+                .peek()
+                .map_or(false, |&(_, character)| character == '\n');
+            if let Some((first_white_space_index, first_white_space_character)) = rev_char_indices
+                .take_while(|&(_, character)| char_is_whitespace(character))
+                .last()
+            {
+                whitespace.start = slice.start + first_white_space_index;
+
+                // If line breaking for a piece of text that has `white-space-collapse: break-spaces` there
+                // is a line break opportunity *after* every preserved space, but not before. This means
+                // that we should not split off the first whitespace, unless that white-space is a preserved
+                // newline.
+                //
+                // An exception to this is if the style tells us that we can break in the middle of words.
+                if text_style.white_space_collapse == WhiteSpaceCollapse::BreakSpaces &&
+                    first_white_space_character != '\n' &&
+                    !can_break_anywhere
+                {
+                    whitespace.start += first_white_space_character.len_utf8();
+                }
+
+                slice.end = whitespace.start;
+            }
+
+            // If there's no whitespace and `word-break` is set to `keep-all`, try increasing the slice.
+            // TODO: This should only happen for CJK text.
+            let can_break_anywhere = text_style.word_break == WordBreak::BreakAll ||
+                text_style.overflow_wrap == OverflowWrap::Anywhere ||
+                text_style.overflow_wrap == OverflowWrap::BreakWord;
+            if whitespace.is_empty() &&
+                *break_index != self.range.end &&
+                text_style.word_break == WordBreak::KeepAll &&
+                !can_break_anywhere
+            {
+                continue;
+            }
+
+            // Only advance the last_slice_end if we are not going to try to expand the slice.
+            last_slice_end = *break_index;
+
+            // Push the non-whitespace part of the range.
+            if !slice.is_empty() {
+                self.shape_and_push_range(&slice, formatting_context_text, &font, shaping_options);
+            }
+
+            if whitespace.is_empty() {
+                continue;
+            }
+
+            let mut options = *shaping_options;
+            options
+                .flags
+                .insert(ShapingFlags::IS_WHITESPACE_SHAPING_FLAG);
+
+            // If `white-space-collapse: break-spaces` is active, insert a line breaking opportunity
+            // between each white space character in the white space that we trimmed off.
+            if text_style.white_space_collapse == WhiteSpaceCollapse::BreakSpaces {
+                let start_index = whitespace.start;
+                for (index, character) in formatting_context_text[whitespace].char_indices() {
+                    let index = start_index + index;
+                    self.shape_and_push_range(
+                        &(index..index + character.len_utf8()),
+                        formatting_context_text,
+                        &font,
+                        &options,
+                    );
+                }
+                continue;
+            }
+
+            // The breaker breaks after every newline, so either there is none,
+            // or there is exactly one at the very end. In the latter case,
+            // split it into a different run. That's because shaping considers
+            // a newline to have the same advance as a space, but during layout
+            // we want to treat the newline as having no advance.
+            if ends_with_newline && whitespace.len() > 1 {
+                self.shape_and_push_range(
+                    &(whitespace.start..whitespace.end - 1),
+                    formatting_context_text,
+                    &font,
+                    &options,
+                );
+                self.shape_and_push_range(
+                    &(whitespace.end - 1..whitespace.end),
+                    formatting_context_text,
+                    &font,
+                    &options,
+                );
+            } else {
+                self.shape_and_push_range(&whitespace, formatting_context_text, &font, &options);
+            }
+        }
+    }
 }
 
 impl TextRun {
@@ -185,14 +337,13 @@ impl TextRun {
         }
     }
 
-    pub(super) fn break_and_shape(
+    pub(super) fn segment_and_shape(
         &mut self,
-        text_content: &str,
+        formatting_context_text: &str,
         font_context: &FontContext<FontCacheThread>,
-        linebreaker: &mut Option<LineBreakLeafIter>,
+        linebreaker: &mut LineBreaker,
         font_cache: &mut Vec<FontKeyAndMetrics>,
     ) {
-        let segment_results = self.segment_text(text_content, font_context, font_cache);
         let inherited_text_style = self.parent_style.get_inherited_text().clone();
         let letter_spacing = if inherited_text_style.letter_spacing.0.px() != 0. {
             Some(app_units::Au::from(inherited_text_style.letter_spacing.0))
@@ -208,13 +359,12 @@ impl TextRun {
             flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
             flags.insert(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
         }
-        if inherited_text_style.word_break == WordBreak::KeepAll {
-            flags.insert(ShapingFlags::KEEP_ALL_FLAG);
-        }
 
         let specified_word_spacing = &inherited_text_style.word_spacing;
         let style_word_spacing: Option<Au> = specified_word_spacing.to_length().map(|l| l.into());
-        let segments = segment_results
+
+        let segments = self
+            .segment_text_by_font(formatting_context_text, font_context, font_cache)
             .into_iter()
             .map(|(mut segment, font)| {
                 let word_spacing = style_word_spacing.unwrap_or_else(|| {
@@ -224,20 +374,21 @@ impl TextRun {
                         .unwrap_or(gfx::font::LAST_RESORT_GLYPH_ADVANCE);
                     specified_word_spacing.to_used_value(Au::from_f64_px(space_width))
                 });
+
                 let shaping_options = ShapingOptions {
                     letter_spacing,
                     word_spacing,
                     script: segment.script,
                     flags,
                 };
-                (segment.runs, segment.break_at_start) = break_and_shape(
-                    font,
-                    &text_content[segment.range.begin().0 as usize..segment.range.end().0 as usize],
-                    &inherited_text_style,
-                    &shaping_options,
-                    linebreaker,
-                );
 
+                segment.shape_text(
+                    &self.parent_style,
+                    formatting_context_text,
+                    linebreaker,
+                    &shaping_options,
+                    font,
+                );
                 segment
             })
             .collect();
@@ -249,9 +400,9 @@ impl TextRun {
     /// font and script. Fonts may differ when glyphs are found in fallback fonts. Fonts are stored
     /// in the `font_cache` which is a cache of all font keys and metrics used in this
     /// [`super::InlineFormattingContext`].
-    fn segment_text(
+    fn segment_text_by_font(
         &mut self,
-        text_content: &str,
+        formatting_context_text: &str,
         font_context: &FontContext<FontCacheThread>,
         font_cache: &mut Vec<FontKeyAndMetrics>,
     ) -> Vec<(TextRunSegment, FontRef)> {
@@ -259,15 +410,16 @@ impl TextRun {
         let mut current: Option<(TextRunSegment, FontRef)> = None;
         let mut results = Vec::new();
 
-        let char_iterator = TwoCharsAtATimeIterator::new(text_content.chars());
-        let mut next_byte_index = 0;
+        let text_run_text = &formatting_context_text[self.text_range.clone()];
+        let char_iterator = TwoCharsAtATimeIterator::new(text_run_text.chars());
+        let mut next_byte_index = self.text_range.start;
         for (character, next_character) in char_iterator {
             let current_byte_index = next_byte_index;
             next_byte_index += character.len_utf8();
 
             let prevents_soft_wrap_opportunity =
                 char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(character);
-            if current_byte_index == 0 && prevents_soft_wrap_opportunity {
+            if current_byte_index == self.text_range.start && prevents_soft_wrap_opportunity {
                 self.prevent_soft_wrap_opportunity_at_start = true;
             }
             self.prevent_soft_wrap_opportunity_at_end = prevents_soft_wrap_opportunity;
@@ -296,17 +448,19 @@ impl TextRun {
 
             // Add the new segment and finish the existing one, if we had one. If the first
             // characters in the run were control characters we may be creating the first
-            // segment in the middle of the run (ie the start should be 0).
+            // segment in the middle of the run (ie the start should be the start of this
+            // text run's text).
             let start_byte_index = match current {
-                Some(_) => ByteIndex(current_byte_index as isize),
-                None => ByteIndex(0_isize),
+                Some(_) => current_byte_index,
+                None => self.text_range.start,
             };
             let new = (
                 TextRunSegment::new(font_index, script, start_byte_index),
                 font,
             );
             if let Some(mut finished) = current.replace(new) {
-                finished.0.range.extend_to(start_byte_index);
+                // The end of the previous segment is the start of the next one.
+                finished.0.range.end = current_byte_index;
                 results.push(finished);
             }
         }
@@ -317,7 +471,7 @@ impl TextRun {
             current = font_group.write().first(font_context).map(|font| {
                 let font_index = add_or_get_font(&font, font_cache);
                 (
-                    TextRunSegment::new(font_index, Script::Common, ByteIndex(0)),
+                    TextRunSegment::new(font_index, Script::Common, self.text_range.start),
                     font,
                 )
             })
@@ -325,10 +479,7 @@ impl TextRun {
 
         // Extend the last segment to the end of the string and add it to the results.
         if let Some(mut last_segment) = current.take() {
-            last_segment
-                .0
-                .range
-                .extend_to(ByteIndex(text_content.len() as isize));
+            last_segment.0.range.end = self.text_range.end;
             results.push(last_segment);
         }
 
@@ -463,129 +614,3 @@ where
         Some((character, self.next_character))
     }
 }
-
-pub fn break_and_shape(
-    font: FontRef,
-    text: &str,
-    text_style: &InheritedText,
-    shaping_options: &ShapingOptions,
-    breaker: &mut Option<LineBreakLeafIter>,
-) -> (Vec<GlyphRun>, bool) {
-    let mut glyphs = vec![];
-
-    if breaker.is_none() {
-        if text.is_empty() {
-            return (glyphs, true);
-        }
-        *breaker = Some(LineBreakLeafIter::new(text, 0));
-    }
-
-    let breaker = breaker.as_mut().unwrap();
-
-    let mut push_range = |range: &Range<usize>, options: &ShapingOptions| {
-        glyphs.push(GlyphRun {
-            glyph_store: font.shape_text(&text[range.clone()], options),
-            range: ServoRange::new(
-                ByteIndex(range.start as isize),
-                ByteIndex(range.len() as isize),
-            ),
-        });
-    };
-
-    let can_break_anywhere = text_style.word_break == WordBreak::BreakAll ||
-        text_style.overflow_wrap == OverflowWrap::Anywhere ||
-        text_style.overflow_wrap == OverflowWrap::BreakWord;
-
-    let mut break_at_zero = false;
-    let mut last_slice_end = 0;
-    while last_slice_end != text.len() {
-        let (break_index, _is_hard_break) = breaker.next(text);
-        if break_index == 0 {
-            break_at_zero = true;
-        }
-
-        // Extend the slice to the next UAX#14 line break opportunity.
-        let mut slice = last_slice_end..break_index;
-        let word = &text[slice.clone()];
-
-        // Split off any trailing whitespace into a separate glyph run.
-        let mut whitespace = slice.end..slice.end;
-        let mut rev_char_indices = word.char_indices().rev().peekable();
-        let ends_with_newline = rev_char_indices.peek().map_or(false, |&(_, c)| c == '\n');
-        if let Some((first_white_space_index, first_white_space_character)) = rev_char_indices
-            .take_while(|&(_, c)| char_is_whitespace(c))
-            .last()
-        {
-            whitespace.start = slice.start + first_white_space_index;
-
-            // If line breaking for a piece of text that has `white-space-collapse: break-spaces` there
-            // is a line break opportunity *after* every preserved space, but not before. This means
-            // that we should not split off the first whitespace, unless that white-space is a preserved
-            // newline.
-            //
-            // An exception to this is if the style tells us that we can break in the middle of words.
-            if text_style.white_space_collapse == WhiteSpaceCollapse::BreakSpaces &&
-                first_white_space_character != '\n' &&
-                !can_break_anywhere
-            {
-                whitespace.start += first_white_space_character.len_utf8();
-            }
-
-            slice.end = whitespace.start;
-        }
-
-        // If there's no whitespace and `word-break` is set to `keep-all`, try increasing the slice.
-        // TODO: This should only happen for CJK text.
-        let can_break_anywhere = text_style.word_break == WordBreak::BreakAll ||
-            text_style.overflow_wrap == OverflowWrap::Anywhere ||
-            text_style.overflow_wrap == OverflowWrap::BreakWord;
-        if whitespace.is_empty() &&
-            break_index != text.len() &&
-            text_style.word_break == WordBreak::KeepAll &&
-            !can_break_anywhere
-        {
-            continue;
-        }
-
-        // Only advance the last_slice_end if we are not going to try to expand the slice.
-        last_slice_end = break_index;
-
-        // Push the non-whitespace part of the range.
-        if !slice.is_empty() {
-            push_range(&slice, shaping_options);
-        }
-
-        if whitespace.is_empty() {
-            continue;
-        }
-
-        let mut options = *shaping_options;
-        options
-            .flags
-            .insert(ShapingFlags::IS_WHITESPACE_SHAPING_FLAG);
-
-        // If `white-space-collapse: break-spaces` is active, insert a line breaking opportunity
-        // between each white space character in the white space that we trimmed off.
-        if text_style.white_space_collapse == WhiteSpaceCollapse::BreakSpaces {
-            let start_index = whitespace.start;
-            for (index, character) in text[whitespace].char_indices() {
-                let index = start_index + index;
-                push_range(&(index..index + character.len_utf8()), &options);
-            }
-            continue;
-        }
-
-        // The breaker breaks after every newline, so either there is none,
-        // or there is exactly one at the very end. In the latter case,
-        // split it into a different run. That's because shaping considers
-        // a newline to have the same advance as a space, but during layout
-        // we want to treat the newline as having no advance.
-        if ends_with_newline && whitespace.len() > 1 {
-            push_range(&(whitespace.start..whitespace.end - 1), &options);
-            push_range(&(whitespace.end - 1..whitespace.end), &options);
-        } else {
-            push_range(&whitespace, &options);
-        }
-    }
-    (glyphs, break_at_zero)
-}
diff --git a/tests/wpt/meta/css/css-text/line-break/line-break-anywhere-overrides-uax-behavior-015.html.ini b/tests/wpt/meta/css/css-text/line-break/line-break-anywhere-overrides-uax-behavior-015.html.ini
new file mode 100644
index 00000000000..a402bca6a59
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/line-break/line-break-anywhere-overrides-uax-behavior-015.html.ini
@@ -0,0 +1,2 @@
+[line-break-anywhere-overrides-uax-behavior-015.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-break/line-break-normal-015b.xht.ini b/tests/wpt/meta/css/css-text/line-break/line-break-normal-015b.xht.ini
deleted file mode 100644
index 45a7609fed1..00000000000
--- a/tests/wpt/meta/css/css-text/line-break/line-break-normal-015b.xht.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-break-normal-015b.xht]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-break/line-break-strict-015b.xht.ini b/tests/wpt/meta/css/css-text/line-break/line-break-strict-015b.xht.ini
deleted file mode 100644
index fcc474b48ee..00000000000
--- a/tests/wpt/meta/css/css-text/line-break/line-break-strict-015b.xht.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-break-strict-015b.xht]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-013.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-013.html.ini
deleted file mode 100644
index e6270623da9..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-013.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-013.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-014.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-014.html.ini
deleted file mode 100644
index d9ffea5b5ee..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-014.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-014.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-021.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-021.html.ini
deleted file mode 100644
index 0301f562755..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-021.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-021.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-024.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-024.html.ini
deleted file mode 100644
index c90a18a4db9..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-024.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-024.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-025.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-025.html.ini
deleted file mode 100644
index 490e03342d8..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-025.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-025.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-026.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-026.html.ini
deleted file mode 100644
index 885652a0c25..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-026.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-026.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-027.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-027.html.ini
deleted file mode 100644
index 7b586c55a96..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-027.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-027.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-010.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-010.html.ini
deleted file mode 100644
index cf5b8690fa8..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-010.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-atomic-010.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-011.html.ini b/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-011.html.ini
deleted file mode 100644
index 239a3ccdfcf..00000000000
--- a/tests/wpt/meta/css/css-text/line-breaking/line-breaking-atomic-011.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[line-breaking-atomic-011.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-001-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-001-ref.html.ini
deleted file mode 100644
index 4dd39974a1f..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-001-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-001-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-002-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-002-ref.html.ini
deleted file mode 100644
index ba8f3bd25c6..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-002-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-002-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-003-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-003-ref.html.ini
deleted file mode 100644
index d7596d53dcd..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-003-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-003-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-008-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-008-ref.html.ini
deleted file mode 100644
index 72e4697e0c4..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-008-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-008-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-009-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-009-ref.html.ini
deleted file mode 100644
index a454e7544d1..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-009-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-009-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-010-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-010-ref.html.ini
deleted file mode 100644
index 5cd24f212ed..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-010-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-010-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-011-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-011-ref.html.ini
deleted file mode 100644
index ae855864b96..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-011-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-011-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-014-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-014-ref.html.ini
deleted file mode 100644
index 720907a8f2e..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-014-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-014-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-016-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-016-ref.html.ini
deleted file mode 100644
index 1e260bb1a34..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-016-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-016-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-020-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-020-ref.html.ini
deleted file mode 100644
index 43014fcbcca..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-020-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-020-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-021-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-021-ref.html.ini
deleted file mode 100644
index b99803ef7f7..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-021-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-021-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/reference/shaping-022-ref.html.ini b/tests/wpt/meta/css/css-text/shaping/reference/shaping-022-ref.html.ini
deleted file mode 100644
index 11850dc34a2..00000000000
--- a/tests/wpt/meta/css/css-text/shaping/reference/shaping-022-ref.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[shaping-022-ref.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-001.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-001.html.ini
new file mode 100644
index 00000000000..b2a8c375d53
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-001.html.ini
@@ -0,0 +1,2 @@
+[shaping-001.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-002.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-002.html.ini
new file mode 100644
index 00000000000..8a834e9d091
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-002.html.ini
@@ -0,0 +1,2 @@
+[shaping-002.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-003.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-003.html.ini
new file mode 100644
index 00000000000..10dbd45d9d5
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-003.html.ini
@@ -0,0 +1,2 @@
+[shaping-003.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-008.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-008.html.ini
new file mode 100644
index 00000000000..ff792047b90
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-008.html.ini
@@ -0,0 +1,2 @@
+[shaping-008.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-014.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-014.html.ini
new file mode 100644
index 00000000000..fea8dc15852
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-014.html.ini
@@ -0,0 +1,2 @@
+[shaping-014.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-016.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-016.html.ini
new file mode 100644
index 00000000000..3080b2780f9
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-016.html.ini
@@ -0,0 +1,2 @@
+[shaping-016.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-017.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-017.html.ini
new file mode 100644
index 00000000000..b1a14fb2c12
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-017.html.ini
@@ -0,0 +1,2 @@
+[shaping-017.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-018.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-018.html.ini
new file mode 100644
index 00000000000..58570ef90b9
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-018.html.ini
@@ -0,0 +1,2 @@
+[shaping-018.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-020.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-020.html.ini
new file mode 100644
index 00000000000..b331edad0ab
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-020.html.ini
@@ -0,0 +1,2 @@
+[shaping-020.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-021.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-021.html.ini
new file mode 100644
index 00000000000..051cd9c380a
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-021.html.ini
@@ -0,0 +1,2 @@
+[shaping-021.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-022.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-022.html.ini
new file mode 100644
index 00000000000..ce3ec82e5e4
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-022.html.ini
@@ -0,0 +1,2 @@
+[shaping-022.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-023.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-023.html.ini
new file mode 100644
index 00000000000..44e9d85cdf3
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-023.html.ini
@@ -0,0 +1,2 @@
+[shaping-023.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-024.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-024.html.ini
new file mode 100644
index 00000000000..0d4e1eba867
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-024.html.ini
@@ -0,0 +1,2 @@
+[shaping-024.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/shaping/shaping-025.html.ini b/tests/wpt/meta/css/css-text/shaping/shaping-025.html.ini
new file mode 100644
index 00000000000..23a42235a3b
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/shaping/shaping-025.html.ini
@@ -0,0 +1,2 @@
+[shaping-025.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/word-break/word-break-manual-001.html.ini b/tests/wpt/meta/css/css-text/word-break/word-break-manual-001.html.ini
new file mode 100644
index 00000000000..3f3a90f56a7
--- /dev/null
+++ b/tests/wpt/meta/css/css-text/word-break/word-break-manual-001.html.ini
@@ -0,0 +1,2 @@
+[word-break-manual-001.html]
+  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/word-break/word-break-normal-002.html.ini b/tests/wpt/meta/css/css-text/word-break/word-break-normal-002.html.ini
deleted file mode 100644
index db03fede0af..00000000000
--- a/tests/wpt/meta/css/css-text/word-break/word-break-normal-002.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[word-break-normal-002.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/word-break/word-break-normal-003.html.ini b/tests/wpt/meta/css/css-text/word-break/word-break-normal-003.html.ini
deleted file mode 100644
index 795ac13c70b..00000000000
--- a/tests/wpt/meta/css/css-text/word-break/word-break-normal-003.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[word-break-normal-003.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-000.html.ini b/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-000.html.ini
deleted file mode 100644
index db1cf94a0b8..00000000000
--- a/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-000.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[word-break-normal-th-000.html]
-  expected: FAIL
diff --git a/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-001.html.ini b/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-001.html.ini
deleted file mode 100644
index ae690e382e8..00000000000
--- a/tests/wpt/meta/css/css-text/word-break/word-break-normal-th-001.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[word-break-normal-th-001.html]
-  expected: FAIL