Backed out 3 changesets (bug 1809568) for causing build bustages on nsLineLayout.cpp. CLOSED TREE

Backed out changeset 573dc0bd9554 (bug 1809568) Backed out changeset b8401947aea0 (bug 1809568) Backed out changeset 7ecabe895121 (bug 1809568)
2023-05-01 17:59:21 +03:00 · 2023-05-01 17:59:21 +03:00 · c9ffb3ffa8
--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@ -3020,7 +3020,6 @@ exports.CSS_PROPERTIES = {
      "float",
      "clear",
      "vertical-align",
-      "baseline-source",
      "overflow-clip-box-inline",
      "overflow-clip-box-block",
      "overflow-x",
@ -4014,23 +4013,6 @@ exports.CSS_PROPERTIES = {
      "unset"
    ]
  },
-  "baseline-source": {
-    "isInherited": false,
-    "subproperties": [
-      "baseline-source"
-    ],
-    "supports": [],
-    "values": [
-      "auto",
-      "first",
-      "inherit",
-      "initial",
-      "last",
-      "revert",
-      "revert-layer",
-      "unset"
-    ]
-  },
  "block-size": {
    "isInherited": false,
    "subproperties": [
--- a/layout/base/Baseline.h
+++ b/layout/base/Baseline.h
@ -19,12 +19,6 @@ enum class BaselineSharingGroup : uint8_t {
  Last = 1,
 };

-// Layout context under which the baseline is being exported to.
-enum class BaselineExportContext : uint8_t {
-  LineLayout = 0,
-  Other = 1,
-};
-
 class Baseline {
 public:
  /**
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@ -5954,8 +5954,8 @@ bool nsLayoutUtils::GetLastLineBaseline(WritingMode aWM, const nsIFrame* aFrame,
    // `ColumnSetWrapperFrame` level, but this keeps it symmetric to
    // `GetFirstLinePosition`.
    if (aFrame->IsColumnSetFrame()) {
-      const auto baseline = aFrame->GetNaturalBaselineBOffset(
-          aWM, BaselineSharingGroup::Last, BaselineExportContext::Other);
+      const auto baseline =
+          aFrame->GetNaturalBaselineBOffset(aWM, BaselineSharingGroup::Last);
      if (!baseline) {
        return false;
      }
--- a/layout/forms/nsCheckboxRadioFrame.cpp
+++ b/layout/forms/nsCheckboxRadioFrame.cpp
@ -86,8 +86,7 @@ LogicalSize nsCheckboxRadioFrame::ComputeAutoSize(
 }

 Maybe<nscoord> nsCheckboxRadioFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  NS_ASSERTION(!IsSubtreeDirty(), "frame must not be dirty");

  if (aBaselineGroup == BaselineSharingGroup::Last) {
--- a/layout/forms/nsCheckboxRadioFrame.h
+++ b/layout/forms/nsCheckboxRadioFrame.h
@ -62,8 +62,8 @@ class nsCheckboxRadioFrame final : public nsAtomicContainerFrame,
                               nsEventStatus* aEventStatus) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  /**
   * Respond to the request to resize and/or reflow
--- a/layout/forms/nsDateTimeControlFrame.cpp
+++ b/layout/forms/nsDateTimeControlFrame.cpp
@ -65,8 +65,7 @@ nscoord nsDateTimeControlFrame::GetPrefISize(gfxContext* aRenderingContext) {
 }

 Maybe<nscoord> nsDateTimeControlFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  return nsTextControlFrame::GetSingleLineTextControlBaseline(
      this, mFirstBaseline, aWM, aBaselineGroup);
 }
--- a/layout/forms/nsDateTimeControlFrame.h
+++ b/layout/forms/nsDateTimeControlFrame.h
@ -62,8 +62,8 @@ class nsDateTimeControlFrame final : public nsContainerFrame {
              nsReflowStatus& aStatus) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  nscoord mFirstBaseline = NS_INTRINSIC_ISIZE_UNKNOWN;
 };
--- a/layout/forms/nsFieldSetFrame.cpp
+++ b/layout/forms/nsFieldSetFrame.cpp
@ -851,8 +851,7 @@ nscoord nsFieldSetFrame::SynthesizeFallbackBaseline(
 }

 Maybe<nscoord> nsFieldSetFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (StyleDisplay()->IsContainLayout()) {
    // If we are layout-contained, our child 'inner' should not
    // affect how we calculate our baseline.
@ -863,8 +862,7 @@ Maybe<nscoord> nsFieldSetFrame::GetNaturalBaselineBOffset(
    return Nothing{};
  }
  MOZ_ASSERT(!inner->GetWritingMode().IsOrthogonalTo(aWM));
-  const auto result =
-      inner->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext);
+  const auto result = inner->GetNaturalBaselineBOffset(aWM, aBaselineGroup);
  if (!result) {
    return Nothing{};
  }
--- a/layout/forms/nsFieldSetFrame.h
+++ b/layout/forms/nsFieldSetFrame.h
@ -41,8 +41,8 @@ class nsFieldSetFrame final : public nsContainerFrame {
      BaselineSharingGroup aBaselineGroup) const override;
  BaselineSharingGroup GetDefaultBaselineSharingGroup() const override;
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  virtual void BuildDisplayList(nsDisplayListBuilder* aBuilder,
                                const nsDisplayListSet& aLists) override;
--- a/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/layout/forms/nsHTMLButtonControlFrame.cpp
@ -313,8 +313,7 @@ void nsHTMLButtonControlFrame::ReflowButtonContents(
 }

 Maybe<nscoord> nsHTMLButtonControlFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (StyleDisplay()->IsContainLayout()) {
    return Nothing{};
  }
@ -323,12 +322,11 @@ Maybe<nscoord> nsHTMLButtonControlFrame::GetNaturalBaselineBOffset(
  if (MOZ_UNLIKELY(inner->GetWritingMode().IsOrthogonalTo(aWM))) {
    return Nothing{};
  }
-  auto result =
-      inner->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext)
-          .valueOrFrom([inner, aWM, aBaselineGroup]() {
-            return Baseline::SynthesizeBOffsetFromBorderBox(inner, aWM,
-                                                            aBaselineGroup);
-          });
+  auto result = inner->GetNaturalBaselineBOffset(aWM, aBaselineGroup)
+                    .valueOrFrom([inner, aWM, aBaselineGroup]() {
+                      return Baseline::SynthesizeBOffsetFromBorderBox(
+                          inner, aWM, aBaselineGroup);
+                    });

  nscoord innerBStart = inner->BStart(aWM, GetSize());
  if (aBaselineGroup == BaselineSharingGroup::First) {
--- a/layout/forms/nsHTMLButtonControlFrame.h
+++ b/layout/forms/nsHTMLButtonControlFrame.h
@ -39,8 +39,8 @@ class nsHTMLButtonControlFrame : public nsContainerFrame,
                      nsReflowStatus& aStatus) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  virtual nsresult HandleEvent(nsPresContext* aPresContext,
                               mozilla::WidgetGUIEvent* aEvent,
--- a/layout/forms/nsListControlFrame.cpp
+++ b/layout/forms/nsListControlFrame.cpp
@ -71,8 +71,7 @@ nsListControlFrame::nsListControlFrame(ComputedStyle* aStyle,
 nsListControlFrame::~nsListControlFrame() = default;

 Maybe<nscoord> nsListControlFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  // Unlike scroll frames which we inherit from, we don't export a baseline.
  return Nothing{};
 }
--- a/layout/forms/nsListControlFrame.h
+++ b/layout/forms/nsListControlFrame.h
@ -56,8 +56,8 @@ class nsListControlFrame final : public nsHTMLScrollFrame,
  NS_DECL_FRAMEARENA_HELPERS(nsListControlFrame)

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  // nsIFrame
  nsresult HandleEvent(nsPresContext* aPresContext,
--- a/layout/forms/nsTextControlFrame.h
+++ b/layout/forms/nsTextControlFrame.h
@ -78,8 +78,8 @@ class nsTextControlFrame : public nsContainerFrame,
              nsReflowStatus& aStatus) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override {
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override {
    if (!IsSingleLineTextControl()) {
      return Nothing{};
    }
--- a/layout/generic/BRFrame.cpp
+++ b/layout/generic/BRFrame.cpp
@ -60,8 +60,7 @@ class BRFrame final : public nsIFrame {
  nscoord GetPrefISize(gfxContext* aRenderingContext) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      WritingMode aWM, BaselineSharingGroup aBaselineGroup) const override;

  bool IsFrameOfType(uint32_t aFlags) const override {
    return nsIFrame::IsFrameOfType(
@ -204,8 +203,7 @@ nscoord BRFrame::GetPrefISize(gfxContext* aRenderingContext) {
 }

 Maybe<nscoord> BRFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::Last) {
    return Nothing{};
  }
--- a/layout/generic/ColumnSetWrapperFrame.cpp
+++ b/layout/generic/ColumnSetWrapperFrame.cpp
@ -235,8 +235,7 @@ nscoord ColumnSetWrapperFrame::GetPrefISize(gfxContext* aRenderingContext) {
 template <typename Iterator>
 Maybe<nscoord> ColumnSetWrapperFrame::GetBaselineBOffset(
    Iterator aStart, Iterator aEnd, WritingMode aWM,
-    BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    BaselineSharingGroup aBaselineGroup) const {
  // Either forward iterator + first baseline, or reverse iterator + last
  // baseline
  MOZ_ASSERT((*aStart == PrincipalChildList().FirstChild() &&
@ -252,8 +251,7 @@ Maybe<nscoord> ColumnSetWrapperFrame::GetBaselineBOffset(
  // baseline.
  for (auto itr = aStart; itr != aEnd; ++itr) {
    const nsIFrame* kid = *itr;
-    auto kidBaseline =
-        kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext);
+    auto kidBaseline = kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup);
    if (!kidBaseline) {
      continue;
    }
@ -272,16 +270,13 @@ Maybe<nscoord> ColumnSetWrapperFrame::GetBaselineBOffset(
 }

 Maybe<nscoord> ColumnSetWrapperFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::First) {
    return GetBaselineBOffset(PrincipalChildList().cbegin(),
-                              PrincipalChildList().cend(), aWM, aBaselineGroup,
-                              aExportContext);
+                              PrincipalChildList().cend(), aWM, aBaselineGroup);
  }
  return GetBaselineBOffset(PrincipalChildList().crbegin(),
-                            PrincipalChildList().crend(), aWM, aBaselineGroup,
-                            aExportContext);
+                            PrincipalChildList().crend(), aWM, aBaselineGroup);
 }

 #ifdef DEBUG
--- a/layout/generic/ColumnSetWrapperFrame.h
+++ b/layout/generic/ColumnSetWrapperFrame.h
@ -60,8 +60,7 @@ class ColumnSetWrapperFrame final : public nsBlockFrame {
  nscoord GetPrefISize(gfxContext* aRenderingContext) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      WritingMode aWM, BaselineSharingGroup aBaselineGroup) const override;

 private:
  explicit ColumnSetWrapperFrame(ComputedStyle* aStyle,
@ -79,8 +78,7 @@ class ColumnSetWrapperFrame final : public nsBlockFrame {
  template <typename Iterator>
  Maybe<nscoord> GetBaselineBOffset(Iterator aStart, Iterator aEnd,
                                    WritingMode aWM,
-                                    BaselineSharingGroup aBaselineGroup,
-                                    BaselineExportContext aExportContext) const;
+                                    BaselineSharingGroup aBaselineGroup) const;
 };

 }  // namespace mozilla
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@ -603,76 +603,54 @@ nscoord nsBlockFrame::SynthesizeFallbackBaseline(
  return Baseline::SynthesizeBOffsetFromMarginBox(this, aWM, aBaselineGroup);
 }

-template <typename LineIterator>
-Maybe<nscoord> nsBlockFrame::GetBaselineBOffset(
-    LineIterator aStart, LineIterator aEnd, WritingMode aWM,
-    BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
-  MOZ_ASSERT((std::is_same_v<LineIterator, ConstLineIterator> &&
-              aBaselineGroup == BaselineSharingGroup::First) ||
-                 (std::is_same_v<LineIterator, ConstReverseLineIterator> &&
-                  aBaselineGroup == BaselineSharingGroup::Last),
-             "Iterator direction must match baseline sharing group.");
-  for (auto line = aStart; line != aEnd; ++line) {
-    if (!line->IsBlock()) {
-      // XXX Is this the right test?  We have some bogus empty lines
-      // floating around, but IsEmpty is perhaps too weak.
-      if (line->BSize() != 0 || !line->IsEmpty()) {
-        const auto ascent = line->BStart() + line->GetLogicalAscent();
-        if (aBaselineGroup == BaselineSharingGroup::Last) {
-          return Some(BSize(aWM) - ascent);
-        }
-        return Some(ascent);
-      }
-      continue;
-    }
-    nsIFrame* kid = line->mFirstChild;
-    if (aWM.IsOrthogonalTo(kid->GetWritingMode())) {
-      continue;
-    }
-    if (aExportContext == BaselineExportContext::LineLayout &&
-        kid->IsTableWrapperFrame()) {
-      // `<table>` in inline-block context does not export any baseline.
-      continue;
-    }
-    const auto kidBaselineGroup =
-        aExportContext == BaselineExportContext::LineLayout
-            ? kid->GetDefaultBaselineSharingGroup()
-            : aBaselineGroup;
-    const auto kidBaseline =
-        kid->GetNaturalBaselineBOffset(aWM, kidBaselineGroup, aExportContext);
-    if (!kidBaseline) {
-      continue;
-    }
-    auto result = *kidBaseline;
-    if (kidBaselineGroup == BaselineSharingGroup::Last) {
-      result = kid->BSize(aWM) - result;
-    }
-    // Ignore relative positioning for baseline calculations.
-    const nsSize& sz = line->mContainerSize;
-    result += kid->GetLogicalNormalPosition(aWM, sz).B(aWM);
-    if (aBaselineGroup == BaselineSharingGroup::Last) {
-      return Some(BSize(aWM) - result);
-    }
-    return Some(result);
-  }
-  return Nothing{};
-}
-
 Maybe<nscoord> nsBlockFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (StyleDisplay()->IsContainLayout()) {
    return Nothing{};
  }

  if (aBaselineGroup == BaselineSharingGroup::First) {
-    return GetBaselineBOffset(LinesBegin(), LinesEnd(), aWM, aBaselineGroup,
-                              aExportContext);
+    nscoord result;
+    if (!nsLayoutUtils::GetFirstLineBaseline(aWM, this, &result)) {
+      return Nothing{};
+    }
+    return Some(result);
  }

-  return GetBaselineBOffset(LinesRBegin(), LinesREnd(), aWM, aBaselineGroup,
-                            aExportContext);
+  for (ConstReverseLineIterator line = LinesRBegin(), line_end = LinesREnd();
+       line != line_end; ++line) {
+    if (line->IsBlock()) {
+      nsIFrame* kid = line->mFirstChild;
+      if (aWM.IsOrthogonalTo(kid->GetWritingMode())) {
+        continue;
+      }
+      if (kid->IsTableWrapperFrame()) {
+        // `<table>` in block display context does not export any baseline.
+        continue;
+      }
+      const auto kidBaselineGroup = kid->GetDefaultBaselineSharingGroup();
+      const auto kidBaseline =
+          kid->GetNaturalBaselineBOffset(aWM, kidBaselineGroup);
+      if (!kidBaseline) {
+        continue;
+      }
+      auto result = *kidBaseline;
+      if (kidBaselineGroup == BaselineSharingGroup::Last) {
+        result = kid->BSize(aWM) - result;
+      }
+      // Ignore relative positioning for baseline calculations.
+      const nsSize& sz = line->mContainerSize;
+      result += kid->GetLogicalNormalPosition(aWM, sz).B(aWM);
+      return Some(BSize(aWM) - result);
+    } else {
+      // XXX Is this the right test?  We have some bogus empty lines
+      // floating around, but IsEmpty is perhaps too weak.
+      if (line->BSize() != 0 || !line->IsEmpty()) {
+        return Some(BSize(aWM) - (line->BStart() + line->GetLogicalAscent()));
+      }
+    }
+  }
+  return Nothing{};
 }

 nscoord nsBlockFrame::GetCaretBaseline() const {
@ -1592,8 +1570,7 @@ void nsBlockFrame::Reflow(nsPresContext* aPresContext, ReflowOutput& aMetrics,
      const auto baselineGroup = BaselineSharingGroup::First;
      Maybe<nscoord> result;
      if (MOZ_LIKELY(!wm.IsOrthogonalTo(marker->GetWritingMode()))) {
-        result = marker->GetNaturalBaselineBOffset(
-            wm, baselineGroup, BaselineExportContext::LineLayout);
+        result = marker->GetNaturalBaselineBOffset(wm, baselineGroup);
      }
      const auto markerBaseline = result.valueOrFrom([bbox, wm, marker]() {
        return bbox.BSize(wm) + marker->GetLogicalUsedMargin(wm).BEnd(wm);
--- a/layout/generic/nsBlockFrame.h
+++ b/layout/generic/nsBlockFrame.h
@ -133,8 +133,8 @@ class nsBlockFrame : public nsContainerFrame {
    return BaselineSharingGroup::Last;
  }
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;
  nscoord GetCaretBaseline() const override;
  void DestroyFrom(nsIFrame* aDestructRoot,
                   PostDestroyData& aPostDestroyData) override;
@ -276,12 +276,6 @@ class nsBlockFrame : public nsContainerFrame {
 private:
  void CheckIntrinsicCacheAgainstShrinkWrapState();

-  template <typename LineIterator>
-  Maybe<nscoord> GetBaselineBOffset(LineIterator aStart, LineIterator aEnd,
-                                    mozilla::WritingMode aWM,
-                                    BaselineSharingGroup aBaselineGroup,
-                                    BaselineExportContext aExportContext) const;
-
 public:
  nscoord GetMinISize(gfxContext* aRenderingContext) override;
  nscoord GetPrefISize(gfxContext* aRenderingContext) override;
--- a/layout/generic/nsColumnSetFrame.cpp
+++ b/layout/generic/nsColumnSetFrame.cpp
@ -1297,12 +1297,10 @@ void nsColumnSetFrame::AppendDirectlyOwnedAnonBoxes(
 }

 Maybe<nscoord> nsColumnSetFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  Maybe<nscoord> result;
  for (const auto* kid : mFrames) {
-    auto kidBaseline =
-        kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext);
+    auto kidBaseline = kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup);
    if (!kidBaseline) {
      continue;
    }
--- a/layout/generic/nsColumnSetFrame.h
+++ b/layout/generic/nsColumnSetFrame.h
@ -75,8 +75,8 @@ class nsColumnSetFrame final : public nsContainerFrame {
                             const nsPoint& aPt);

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

 protected:
  nscoord mLastBalanceBSize;
--- a/layout/generic/nsFirstLetterFrame.cpp
+++ b/layout/generic/nsFirstLetterFrame.cpp
@ -426,8 +426,7 @@ void nsFirstLetterFrame::DrainOverflowFrames(nsPresContext* aPresContext) {
 }

 Maybe<nscoord> nsFirstLetterFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::Last) {
    return Nothing{};
  }
--- a/layout/generic/nsFirstLetterFrame.h
+++ b/layout/generic/nsFirstLetterFrame.h
@ -61,8 +61,8 @@ class nsFirstLetterFrame final : public nsContainerFrame {

  virtual bool CanContinueTextRun() const override;
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;
  virtual LogicalSides GetLogicalSkipSides() const override;

  // override of nsFrame method
--- a/layout/generic/nsFlexContainerFrame.cpp
+++ b/layout/generic/nsFlexContainerFrame.cpp
@ -416,8 +416,7 @@ class nsFlexContainerFrame::FlexItem final {
    // If the nsLayoutUtils getter fails, then ask the frame directly:
    auto baselineGroup = aUseFirstBaseline ? BaselineSharingGroup::First
                                           : BaselineSharingGroup::Last;
-    if (auto baseline = mFrame->GetNaturalBaselineBOffset(
-            mWM, baselineGroup, BaselineExportContext::Other)) {
+    if (auto baseline = mFrame->GetNaturalBaselineBOffset(mWM, baselineGroup)) {
      // Offset for last baseline from `GetNaturalBaselineBOffset` originates
      // from the frame's block end, so convert it back.
      mAscent = baselineGroup == BaselineSharingGroup::First
@ -4637,8 +4636,7 @@ void nsFlexContainerFrame::Reflow(nsPresContext* aPresContext,
 }

 Maybe<nscoord> nsFlexContainerFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (StyleDisplay()->IsContainLayout() ||
      HasAnyStateBits(NS_STATE_FLEX_SYNTHESIZE_BASELINE)) {
    return Nothing{};
--- a/layout/generic/nsFlexContainerFrame.h
+++ b/layout/generic/nsFlexContainerFrame.h
@ -166,8 +166,8 @@ class nsFlexContainerFrame final : public nsContainerFrame,
 #endif

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  // Unions the child overflow from our in-flow children.
  void UnionInFlowChildOverflow(mozilla::OverflowAreas&);
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@ -1421,8 +1421,7 @@ nscoord nsHTMLScrollFrame::SynthesizeFallbackBaseline(
 }

 Maybe<nscoord> nsHTMLScrollFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  // Block containers that are scrollable always have a last baseline
  // that are synthesized from block-end margin edge.
  // Note(dshin): This behaviour is really only relevant to `inline-block`
@ -1430,8 +1429,7 @@ Maybe<nscoord> nsHTMLScrollFrame::GetNaturalBaselineBOffset(
  // baselines are calculated through `GetFirstLineBaseline`, which does
  // calculations of its own.
  // https://drafts.csswg.org/css-align/#baseline-export
-  if (aExportContext == BaselineExportContext::LineLayout &&
-      aBaselineGroup == BaselineSharingGroup::Last &&
+  if (aBaselineGroup == BaselineSharingGroup::Last &&
      mScrolledFrame->IsBlockFrameOrSubclass()) {
    return Some(SynthesizeFallbackBaseline(aWM, aBaselineGroup));
  }
@ -1441,8 +1439,7 @@ Maybe<nscoord> nsHTMLScrollFrame::GetNaturalBaselineBOffset(
  }

  // OK, here's where we defer to our scrolled frame.
-  return mScrolledFrame
-      ->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext)
+  return mScrolledFrame->GetNaturalBaselineBOffset(aWM, aBaselineGroup)
      .map([this, aWM](nscoord aBaseline) {
        // We have to add our border BStart thickness to whatever it returns, to
        // produce an offset in our frame-rect's coordinate system. (We don't
--- a/layout/generic/nsGfxScrollFrame.h
+++ b/layout/generic/nsGfxScrollFrame.h
@ -130,8 +130,8 @@ class nsHTMLScrollFrame : public nsContainerFrame,
      mozilla::WritingMode aWM,
      BaselineSharingGroup aBaselineGroup) const override;
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  // Recomputes the scrollable overflow area we store in the helper to take
  // children that are affected by perpsective set on the outer frame and scroll
--- a/layout/generic/nsGridContainerFrame.cpp
+++ b/layout/generic/nsGridContainerFrame.cpp
@ -9568,9 +9568,7 @@ nscoord nsGridContainerFrame::SynthesizeBaseline(
      baseline = isOrthogonal ? grid->GetIBaseline(aGroup)
                              : grid->GetBBaseline(aGroup);
    } else if (!isOrthogonal && aGridOrderItem.mIsInEdgeTrack) {
-      baseline = child
-                     ->GetNaturalBaselineBOffset(childWM, aGroup,
-                                                 BaselineExportContext::Other)
+      baseline = child->GetNaturalBaselineBOffset(childWM, aGroup)
                     .valueOrFrom([aGroup, child, childWM]() {
                       return Baseline::SynthesizeBOffsetFromBorderBox(
                           child, childWM, aGroup);
--- a/layout/generic/nsGridContainerFrame.h
+++ b/layout/generic/nsGridContainerFrame.h
@ -131,8 +131,8 @@ class nsGridContainerFrame final : public nsContainerFrame,
                        const nsDisplayListSet& aLists) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override {
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override {
    if (StyleDisplay()->IsContainLayout() ||
        HasAnyStateBits(NS_STATE_GRID_SYNTHESIZE_BASELINE)) {
      return Nothing{};
--- a/layout/generic/nsIFrame.cpp
+++ b/layout/generic/nsIFrame.cpp
@ -2092,15 +2092,13 @@ nscoord nsIFrame::SynthesizeFallbackBaseline(
 }

 nscoord nsIFrame::GetLogicalBaseline(WritingMode aWM) const {
-  return GetLogicalBaseline(aWM, GetDefaultBaselineSharingGroup(),
-                            BaselineExportContext::LineLayout);
+  return GetLogicalBaseline(aWM, GetDefaultBaselineSharingGroup());
 }

 nscoord nsIFrame::GetLogicalBaseline(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  const auto result =
-      GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext)
+      GetNaturalBaselineBOffset(aWM, aBaselineGroup)
          .valueOrFrom([this, aWM, aBaselineGroup]() {
            return SynthesizeFallbackBaseline(aWM, aBaselineGroup);
          });
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@ -519,7 +519,6 @@ class nsIFrame : public nsQueryFrame {
 public:
  using AlignmentContext = mozilla::AlignmentContext;
  using BaselineSharingGroup = mozilla::BaselineSharingGroup;
-  using BaselineExportContext = mozilla::BaselineExportContext;
  template <typename T>
  using Maybe = mozilla::Maybe<T>;
  template <typename T, typename E>
@ -1529,19 +1528,14 @@ class nsIFrame : public nsQueryFrame {

  /**
   * `GetNaturalBaselineBOffset`, but determines the baseline sharing group
-   * through `GetDefaultBaselineSharingGroup` (If not specified), assuming line
-   * layout context, and never fails, returning a synthesized baseline through
+   * through `GetDefaultBaselineSharingGroup` (If not specified), and never
+   * fails, returning a synthesized baseline through
   * `SynthesizeFallbackBaseline`. Unlike `GetNaturalBaselineBOffset`, Result is
   * always relative to the block start of the frame.
   */
  nscoord GetLogicalBaseline(mozilla::WritingMode aWM) const;
-  /**
-   * Same as the above, but with baseline sharing group & export
-   * context specified.
-   */
  nscoord GetLogicalBaseline(mozilla::WritingMode aWM,
-                             BaselineSharingGroup aBaselineGroup,
-                             BaselineExportContext aExportContext) const;
+                             BaselineSharingGroup aBaselineGroup) const;

  /**
   * Return true if the frame has a first(last) inline-axis baseline per
@ -1549,21 +1543,14 @@ class nsIFrame : public nsQueryFrame {
   * the relevant block-axis border-box edge (Start for
   * BaselineSharingGroup::First, end for BaselineSharingGroup::Last), where
   * a positive value points towards the content-box.
-   * Some frames can export different baselines depending if it's in a line
-   * layout context or any other context (e.g. Flex, grid).
   * https://drafts.csswg.org/css-align-3/#baseline-export
   * @note The returned value is only valid when reflow is not needed.
   * @note You should only call this on frames with a WM that's parallel to aWM.
-   * @note We're approaching `nsLayoutUtils::Get(First|Last)LineBaseline` ==
-   * `GetNaturalBaselineBOffset(aWM, (First|Last), Other)`. Grid relies on
-   * baseline synthesis behaviour in `nsLayoutUtils` implementations (bug
-   * 1609403), which blocks its removal.
   * @param aWM the writing-mode of the alignment context.
   * @return the baseline offset, if one exists
   */
  virtual Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const {
+      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
    return Nothing{};
  }

@ -1670,8 +1657,7 @@ class nsIFrame : public nsQueryFrame {

 public:
  /**
-   * Get the suitable baseline sharing group for this element, assuming line
-   * layout.
+   * Get the suitable baseline sharing group for this element.
   */
  virtual BaselineSharingGroup GetDefaultBaselineSharingGroup() const {
    return BaselineSharingGroup::First;
--- a/layout/generic/nsInlineFrame.cpp
+++ b/layout/generic/nsInlineFrame.cpp
@ -841,8 +841,7 @@ LogicalSides nsInlineFrame::GetLogicalSkipSides() const {
 }

 Maybe<nscoord> nsInlineFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::Last) {
    return Nothing{};
  }
--- a/layout/generic/nsInlineFrame.h
+++ b/layout/generic/nsInlineFrame.h
@ -97,8 +97,8 @@ class nsInlineFrame : public nsContainerFrame {
  virtual void PullOverflowsFromPrevInFlow() override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;
  virtual bool DrainSelfOverflowList() override;

  /**
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@ -1335,18 +1335,6 @@ bool nsLineLayout::CanPlaceFrame(PerFrameData* pfd, bool aNotSafeToBreak,
  return false;
 }

-BaselineSharingGroup BaselineSourceToBaselineSharingGroup(
-    const nsIFrame& aFrame) {
-  switch (aFrame.StyleDisplay()->mBaselineSource) {
-    case StyleBaselineSource::First:
-      return BaselineSharingGroup::First;
-    case StyleBaselineSource::Last:
-      return BaselineSharingGroup::Last;
-    case StyleBaselineSource::Auto:
-      return aFrame.GetDefaultBaselineSharingGroup();
-  }
-}
-
 /**
 * Place the frame. Update running counters.
 */
@ -1361,32 +1349,10 @@ void nsLineLayout::PlaceFrame(PerFrameData* pfd, ReflowOutput& aMetrics) {
                       ? lineWM.IsLineInverted() ? 0 : aMetrics.BSize(lineWM)
                       : aMetrics.BSize(lineWM) / 2;
  } else {
-    if (pfd->mFrame->StyleDisplay()->mBaselineSource ==
-        StyleBaselineSource::Auto) {
-      if (aMetrics.BlockStartAscent() == ReflowOutput::ASK_FOR_BASELINE) {
-        pfd->mAscent = pfd->mFrame->GetLogicalBaseline(lineWM);
-      } else {
-        pfd->mAscent = aMetrics.BlockStartAscent();
-      }
+    if (aMetrics.BlockStartAscent() == ReflowOutput::ASK_FOR_BASELINE) {
+      pfd->mAscent = pfd->mFrame->GetLogicalBaseline(lineWM);
    } else {
-      const auto sourceGroup = [pfd]() {
-        switch (pfd->mFrame->StyleDisplay()->mBaselineSource) {
-          case StyleBaselineSource::First:
-            return BaselineSharingGroup::First;
-          case StyleBaselineSource::Last:
-            return BaselineSharingGroup::Last;
-          case StyleBaselineSource::Auto:
-            break;
-        }
-        MOZ_ASSERT_UNREACHABLE("Auto should be already handled?");
-      }();
-      // We ignore line-layout specific layout quirks by setting
-      // `BaselineExportContext::Other`.
-      // Note(dshin): For a lot of frames, the export context does not make a
-      // difference, and we may be wasting the value cached in
-      // `BlockStartAscent`.
-      pfd->mAscent = pfd->mFrame->GetLogicalBaseline(
-          lineWM, sourceGroup, BaselineExportContext::Other);
+      pfd->mAscent = aMetrics.BlockStartAscent();
    }
  }

@ -1450,6 +1416,7 @@ void nsLineLayout::RemoveMarkerFrame(nsIFrame* aFrame) {
  psd->mFirstFrame = pfd->mNext;
  FreeFrame(pfd);
 }
+
 #ifdef DEBUG
 void nsLineLayout::DumpPerSpanData(PerSpanData* psd, int32_t aIndent) {
  nsIFrame::IndentBy(stdout, aIndent);
--- a/layout/generic/nsRubyBaseContainerFrame.cpp
+++ b/layout/generic/nsRubyBaseContainerFrame.cpp
@ -262,8 +262,7 @@ nsIFrame::SizeComputationResult nsRubyBaseContainerFrame::ComputeSize(
 }

 Maybe<nscoord> nsRubyBaseContainerFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::Last) {
    return Nothing{};
  }
--- a/layout/generic/nsRubyBaseContainerFrame.h
+++ b/layout/generic/nsRubyBaseContainerFrame.h
@ -47,8 +47,8 @@ class nsRubyBaseContainerFrame final : public nsContainerFrame {
                      nsReflowStatus& aStatus) override;

  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

 #ifdef DEBUG_FRAME_DUMP
  virtual nsresult GetFrameName(nsAString& aResult) const override;
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@ -10058,8 +10058,7 @@ bool nsTextFrame::IsAtEndOfLine() const {
 }

 Maybe<nscoord> nsTextFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (aBaselineGroup == BaselineSharingGroup::Last) {
    return Nothing{};
  }
--- a/layout/generic/nsTextFrame.h
+++ b/layout/generic/nsTextFrame.h
@ -367,8 +367,8 @@ class nsTextFrame : public nsIFrame {
  bool IsEmpty() final;
  bool IsSelfEmpty() final { return IsEmpty(); }
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  bool HasSignificantTerminalNewline() const final;

--- a/layout/style/ServoBindings.toml
+++ b/layout/style/ServoBindings.toml
@ -646,7 +646,6 @@ cbindgen-types = [
    { gecko = "StyleFontSynthesis", servo = "crate::values::computed::font::FontSynthesis" },
    { gecko = "StyleBoolInteger", servo = "crate::values::computed::BoolInteger" },
    { gecko = "StyleTime", servo = "crate::values::computed::Time" },
-    { gecko = "StyleBaselineSource", servo = "crate::values::computed::BaselineSource" },
 ]

 mapped-generic-types = [
--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@ -2224,7 +2224,6 @@ nsStyleDisplay::nsStyleDisplay(const Document& aDocument)
      mPerspectiveOrigin(Position::FromPercentage(0.5f)),
      mVerticalAlign(
          StyleVerticalAlign::Keyword(StyleVerticalAlignKeyword::Baseline)),
-      mBaselineSource(StyleBaselineSource::Auto),
      mWebkitLineClamp(0),
      mShapeMargin(LengthPercentage::Zero()),
      mShapeOutside(StyleShapeOutside::None()) {
@ -2280,7 +2279,6 @@ nsStyleDisplay::nsStyleDisplay(const nsStyleDisplay& aSource)
      mChildPerspective(aSource.mChildPerspective),
      mPerspectiveOrigin(aSource.mPerspectiveOrigin),
      mVerticalAlign(aSource.mVerticalAlign),
-      mBaselineSource(aSource.mBaselineSource),
      mWebkitLineClamp(aSource.mWebkitLineClamp),
      mShapeImageThreshold(aSource.mShapeImageThreshold),
      mShapeMargin(aSource.mShapeMargin),
@ -2517,8 +2515,7 @@ nsChangeHint nsStyleDisplay::CalcDifference(
  }

  if (mWebkitLineClamp != aNewData.mWebkitLineClamp ||
-      mVerticalAlign != aNewData.mVerticalAlign ||
-      mBaselineSource != aNewData.mBaselineSource) {
+      mVerticalAlign != aNewData.mVerticalAlign) {
    // XXX Can this just be AllReflowHints + RepaintFrame, and be included in
    // the block below?
    hint |= NS_STYLE_HINT_REFLOW;
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@ -1381,7 +1381,6 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleDisplay {
  mozilla::Position mPerspectiveOrigin;

  mozilla::StyleVerticalAlign mVerticalAlign;
-  mozilla::StyleBaselineSource mBaselineSource;

  mozilla::StyleLineClamp mWebkitLineClamp;

--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@ -8418,17 +8418,6 @@ var gCSSProperties = {
    invalid_values: [],
    quirks_values: { "5": "5px" },
  },
-  "baseline-source": {
-    domProp: "baselineSource",
-    inherited: false,
-    type: CSS_TYPE_LONGHAND,
-    applies_to_first_letter: true,
-    applies_to_first_line: true,
-    applies_to_placeholder: true,
-    initial_values: ["auto"],
-    other_values: ["first", "last"],
-    invalid_values: [],
-  },
  visibility: {
    domProp: "visibility",
    inherited: true,
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@ -3542,8 +3542,7 @@ nscoord nsTableFrame::SynthesizeFallbackBaseline(

 /* virtual */
 Maybe<nscoord> nsTableFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  if (StyleDisplay()->IsContainLayout()) {
    return Nothing{};
  }
--- a/layout/tables/nsTableFrame.h
+++ b/layout/tables/nsTableFrame.h
@ -439,8 +439,8 @@ class nsTableFrame : public nsContainerFrame {
      mozilla::WritingMode aWM,
      BaselineSharingGroup aBaselineGroup) const override;
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  /** return the row span of a cell, taking into account row span magic at the
   * bottom of a table. The row span equals the number of rows spanned by aCell
--- a/layout/tables/nsTableWrapperFrame.cpp
+++ b/layout/tables/nsTableWrapperFrame.cpp
@ -41,8 +41,7 @@ nscoord nsTableWrapperFrame::SynthesizeFallbackBaseline(
 }

 Maybe<nscoord> nsTableWrapperFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-    BaselineExportContext aExportContext) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
  // Baseline is determined by row
  // (https://drafts.csswg.org/css-align-3/#baseline-export). If the row
  // direction is going to be orthogonal to the parent's writing mode, the
@ -53,8 +52,7 @@ Maybe<nscoord> nsTableWrapperFrame::GetNaturalBaselineBOffset(
    return Nothing{};
  }
  auto* innerTable = InnerTableFrame();
-  return innerTable
-      ->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext)
+  return innerTable->GetNaturalBaselineBOffset(aWM, aBaselineGroup)
      .map([this, aWM, aBaselineGroup, innerTable](nscoord aBaseline) {
        auto bStart = innerTable->BStart(aWM, mRect.Size());
        if (aBaselineGroup == BaselineSharingGroup::First) {
--- a/layout/tables/nsTableWrapperFrame.h
+++ b/layout/tables/nsTableWrapperFrame.h
@ -68,8 +68,8 @@ class nsTableWrapperFrame : public nsContainerFrame {
      mozilla::WritingMode aWM,
      BaselineSharingGroup aBaselineGroup) const override;
  Maybe<nscoord> GetNaturalBaselineBOffset(
-      mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
-      BaselineExportContext aExportContext) const override;
+      mozilla::WritingMode aWM,
+      BaselineSharingGroup aBaselineGroup) const override;

  virtual nscoord GetMinISize(gfxContext* aRenderingContext) override;
  virtual nscoord GetPrefISize(gfxContext* aRenderingContext) override;
--- a/servo/components/style/properties/data.py
+++ b/servo/components/style/properties/data.py
@ -447,7 +447,6 @@ class Longhand(Property):
                "AlignSelf",
                "Appearance",
                "AspectRatio",
-                "BaselineSource",
                "BreakBetween",
                "BreakWithin",
                "BackgroundRepeat",
--- a/servo/components/style/properties/longhands/box.mako.rs
+++ b/servo/components/style/properties/longhands/box.mako.rs
@ -94,16 +94,6 @@ ${helpers.predefined_type(
    servo_restyle_damage = "reflow",
 )}

-${helpers.predefined_type(
-    "baseline-source",
-    "BaselineSource",
-    "computed::BaselineSource::Auto",
-    engines="gecko servo-2013",
-    animation_value_type="discrete",
-    spec="https://drafts.csswg.org/css-inline-3/#baseline-source",
-    servo_restyle_damage = "reflow",
-)}
-
 // CSS 2.1, Section 11 - Visual effects

 ${helpers.single_keyword(
--- a/servo/components/style/values/computed/box.rs
+++ b/servo/components/style/values/computed/box.rs
@ -18,7 +18,7 @@ pub use crate::values::specified::box_::{
    Float as SpecifiedFloat, Overflow, OverflowAnchor, OverflowClipBox, OverscrollBehavior,
    ScrollAxis, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop, ScrollSnapStrictness,
    ScrollSnapType, ScrollTimelineName, ScrollbarGutter, TouchAction, TransitionProperty,
-    WillChange, BaselineSource,
+    WillChange,
 };

 use std::fmt::{self, Write};
--- a/servo/components/style/values/computed/mod.rs
+++ b/servo/components/style/values/computed/mod.rs
@ -58,7 +58,7 @@ pub use self::box_::{Display, LineClamp, Overflow, OverflowAnchor, TransitionPro
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, ScrollbarGutter};
 pub use self::box_::{ScrollAxis, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
 pub use self::box_::{ScrollSnapStrictness, ScrollSnapType, ScrollTimelineName};
-pub use self::box_::{TouchAction, VerticalAlign, WillChange, BaselineSource};
+pub use self::box_::{TouchAction, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust, ForcedColorAdjust};
 pub use self::column::ColumnCount;
 pub use self::counters::{Content, ContentItem, CounterIncrement, CounterReset, CounterSet};
--- a/servo/components/style/values/specified/box.rs
+++ b/servo/components/style/values/specified/box.rs
@ -637,33 +637,6 @@ impl Parse for VerticalAlign {
    }
 }

-/// A specified value for the `baseline-source` property.
-/// https://drafts.csswg.org/css-inline-3/#baseline-source
-#[derive(
-    Clone,
-    Copy,
-    Debug,
-    Eq,
-    Hash,
-    MallocSizeOf,
-    Parse,
-    PartialEq,
-    SpecifiedValueInfo,
-    ToCss,
-    ToShmem,
-    ToComputedValue,
-    ToResolvedValue,
-)]
-#[repr(u8)]
-pub enum BaselineSource {
-    /// `Last` for `inline-block`, `First` otherwise.
-    Auto,
-    /// Use first baseline for alignment.
-    First,
-    /// Use last baseline for alignment.
-    Last,
-}
-
 /// https://drafts.csswg.org/css-animations/#animation-iteration-count
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, Parse, SpecifiedValueInfo, ToCss, ToShmem)]
 pub enum AnimationIterationCount {
--- a/servo/components/style/values/specified/mod.rs
+++ b/servo/components/style/values/specified/mod.rs
@ -44,7 +44,7 @@ pub use self::box_::{
 pub use self::box_::{OverflowClipBox, OverscrollBehavior, Perspective, Resize, ScrollbarGutter};
 pub use self::box_::{ScrollAxis, ScrollSnapAlign, ScrollSnapAxis, ScrollSnapStop};
 pub use self::box_::{ScrollSnapStrictness, ScrollSnapType, ScrollTimelineName};
-pub use self::box_::{TouchAction, TransitionProperty, VerticalAlign, WillChange, BaselineSource};
+pub use self::box_::{TouchAction, TransitionProperty, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorOrAuto, ColorPropertyValue, ColorScheme, PrintColorAdjust, ForcedColorAdjust};
 pub use self::column::ColumnCount;
 pub use self::counters::{Content, ContentItem, CounterIncrement, CounterReset, CounterSet};
--- a/servo/ports/geckolib/cbindgen.toml
+++ b/servo/ports/geckolib/cbindgen.toml
@ -147,7 +147,6 @@ include = [
  "Position",
  "PositionOrAuto",
  "BackgroundSize",
-  "BaselineSource",
  "BorderImageSlice",
  "BorderSpacing",
  "BorderRadius",
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-computed.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-computed.html.ini
@ -0,0 +1,9 @@
+[baseline-source-computed.html]
+  [Property baseline-source value 'auto']
+    expected: FAIL
+
+  [Property baseline-source value 'first']
+    expected: FAIL
+
+  [Property baseline-source value 'last']
+    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-001.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-001.html.ini
@ -0,0 +1,21 @@
+[baseline-source-first-001.html]
+  [.target > * 1]
+    expected: FAIL
+
+  [.target > * 3]
+    expected: FAIL
+
+  [.target > * 5]
+    expected: FAIL
+
+  [.target > * 7]
+    expected: FAIL
+
+  [.target > * 9]
+    expected: FAIL
+
+  [.target > * 15]
+    expected: FAIL
+
+  [.target > * 21]
+    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-002.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-002.html.ini
@ -1,8 +1,30 @@
 [baseline-source-first-002.html]
+  [.target > * 1]
+    expected: FAIL
+
+  [.target > * 3]
+    expected: FAIL
+
+  [.target > * 4]
+    expected: FAIL
+
+  [.target > * 5]
+    expected: FAIL
+
+  [.target > * 7]
+    expected: FAIL
+
+  [.target > * 9]
+    expected: FAIL
+
+  [.target > * 10]
+    expected: FAIL
+
+  [.target > * 15]
+    expected: FAIL
+
  [.target > * 19]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
    expected: FAIL

  [.target > * 21]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-003.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-first-003.html.ini
@ -0,0 +1,21 @@
+[baseline-source-first-003.html]
+  [.target > * 1]
+    expected: FAIL
+
+  [.target > * 3]
+    expected: FAIL
+
+  [.target > * 5]
+    expected: FAIL
+
+  [.target > * 7]
+    expected: FAIL
+
+  [.target > * 9]
+    expected: FAIL
+
+  [.target > * 15]
+    expected: FAIL
+
+  [.target > * 21]
+    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-invalid.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-invalid.html.ini
@ -0,0 +1,3 @@
+[baseline-source-invalid.html]
+  expected:
+    if (os == "android") and fission: [TIMEOUT, OK]
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-001.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-001.html.ini
@ -1,16 +1,21 @@
 [baseline-source-last-001.html]
+  [.target > * 3]
+    expected: FAIL
+
  [.target > * 9]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827484
    expected: FAIL

  [.target > * 11]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
+    expected: FAIL
+
+  [.target > * 13]
    expected: FAIL

  [.target > * 17]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
    expected: FAIL

  [.target > * 19]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
+    expected: FAIL
+
+  [.target > * 21]
    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-002.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-002.html.ini
@ -1,24 +1,30 @@
 [baseline-source-last-002.html]
+  [.target > * 3]
+    expected: FAIL
+
+  [.target > * 4]
+    expected: FAIL
+
+  [.target > * 5]
+    expected: FAIL
+
  [.target > * 9]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827484
    expected: FAIL

  [.target > * 10]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827484
    expected: FAIL

  [.target > * 11]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
+    expected: FAIL
+
+  [.target > * 13]
    expected: FAIL

  [.target > * 17]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
    expected: FAIL

  [.target > * 19]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
    expected: FAIL

  [.target > * 21]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-003.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-last-003.html.ini
@ -1,16 +1,24 @@
 [baseline-source-last-003.html]
+  [.target > * 3]
+    expected: FAIL
+
+  [.target > * 5]
+    expected: FAIL
+
  [.target > * 9]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827484
    expected: FAIL

  [.target > * 11]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
+    expected: FAIL
+
+  [.target > * 13]
    expected: FAIL

  [.target > * 17]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1827481
    expected: FAIL

  [.target > * 19]
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=144517
+    expected: FAIL
+
+  [.target > * 21]
    expected: FAIL
--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-no-interpolation.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-no-interpolation.html.ini
@ -1,5 +1,79 @@
 [baseline-source-no-interpolation.html]
-  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1805727
+  [CSS Transitions: property <baseline-source> from [initial\] to [last\] at (0.5) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions: property <baseline-source> from [initial\] to [last\] at (0.6) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions: property <baseline-source> from [initial\] to [last\] at (1) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions: property <baseline-source> from [initial\] to [last\] at (1.5) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (-0.3) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (0) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (0.3) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (0.5) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (0.6) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (1) should be [last\]]
+    expected: FAIL
+
+  [CSS Transitions with transition: all: property <baseline-source> from [initial\] to [last\] at (1.5) should be [last\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (-0.3) should be [initial\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (0) should be [initial\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (0.3) should be [initial\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (0.5) should be [last\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (0.6) should be [last\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (1) should be [last\]]
+    expected: FAIL
+
+  [CSS Animations: property <baseline-source> from [initial\] to [last\] at (1.5) should be [last\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (-0.3) should be [initial\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (0) should be [initial\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (0.3) should be [initial\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (0.5) should be [last\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (0.6) should be [last\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (1) should be [last\]]
+    expected: FAIL
+
+  [Web Animations: property <baseline-source> from [initial\] to [last\] at (1.5) should be [last\]]
+    expected: FAIL
+
  [CSS Transitions: property <baseline-source> from [initial\] to [last\] at (0) should be [initial\]]
    expected: FAIL

--- a/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-valid.html.ini
+++ b/testing/web-platform/meta/css/css-inline/baseline-source/baseline-source-valid.html.ini
@ -0,0 +1,9 @@
+[baseline-source-valid.html]
+  [e.style['baseline-source'\] = "auto" should set the property value]
+    expected: FAIL
+
+  [e.style['baseline-source'\] = "first" should set the property value]
+    expected: FAIL
+
+  [e.style['baseline-source'\] = "last" should set the property value]
+    expected: FAIL