diff --git a/components/layout/block.rs b/components/layout/block.rs
index 003f1fb2e02..351b0dba9d9 100644
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@@ -1417,7 +1417,7 @@ impl BlockFlow {
             // Per CSS 2.1 § 16.3.1, text alignment propagates to all children in flow.
             //
             // TODO(#2265, pcwalton): Do this in the cascade instead.
-            let containing_block_text_align = self.fragment.style().get_inheritedtext().text_align;
+            let containing_block_text_align = self.fragment.style().get_inherited_text().text_align;
             kid.mut_base().flags.set_text_align(containing_block_text_align);
 
             // Handle `text-indent` on behalf of any inline children that we have. This is
@@ -1425,7 +1425,7 @@ impl BlockFlow {
             // we know.
             if kid.is_inline_flow() {
                 kid.as_mut_inline().first_line_indentation =
-                    self.fragment.style().get_inheritedtext().text_indent
+                    self.fragment.style().get_inherited_text().text_indent
                         .to_used_value(containing_block_size);
             }
         }
@@ -2340,7 +2340,7 @@ pub trait ISizeAndMarginsComputer {
                                                         containing_block_inline_size),
                                   MaybeAuto::from_style(position.inline_end,
                                                         containing_block_inline_size),
-                                  style.get_inheritedtext().text_align,
+                                  style.get_inherited_text().text_align,
                                   available_inline_size)
     }
 
diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index efa3ccd176a..063b1ee710f 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -1095,7 +1095,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                         kid_flow.as_block()
                                 .fragment
                                 .style()
-                                .get_inheritedtable()
+                                .get_inherited_table()
                                 .caption_side == side {
                         table_wrapper_flow.add_new_child(kid_flow);
                     }
@@ -1256,7 +1256,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         // Determine if the table cell should be hidden. Per CSS 2.1 § 17.6.1.1, this will be true
         // if the cell has any in-flow elements (even empty ones!) and has `empty-cells` set to
         // `hide`.
-        let hide = node.style(self.style_context()).get_inheritedtable().empty_cells == EmptyCells::Hide &&
+        let hide = node.style(self.style_context()).get_inherited_table().empty_cells == EmptyCells::Hide &&
             node.children().all(|kid| {
                 let position = kid.style(self.style_context()).get_box().position;
                 !kid.is_content() ||
@@ -1871,7 +1871,7 @@ fn bidi_control_chars(style: &ServoArc<ComputedValues>) -> Option<(&'static str,
     use style::computed_values::unicode_bidi::T::*;
 
     let unicode_bidi = style.get_text().unicode_bidi;
-    let direction = style.get_inheritedbox().direction;
+    let direction = style.get_inherited_box().direction;
 
     // See the table in http://dev.w3.org/csswg/css-writing-modes/#unicode-bidi
     match (unicode_bidi, direction) {
diff --git a/components/layout/display_list/builder.rs b/components/layout/display_list/builder.rs
index 16a1fc85770..d8467958038 100644
--- a/components/layout/display_list/builder.rs
+++ b/components/layout/display_list/builder.rs
@@ -1013,7 +1013,7 @@ impl FragmentDisplayListBuilding for Fragment {
                 id: webrender_image.key.unwrap(),
                 stretch_size: placement.tile_size.to_layout(),
                 tile_spacing: placement.tile_spacing.to_layout(),
-                image_rendering: style.get_inheritedbox().image_rendering.to_layout(),
+                image_rendering: style.get_inherited_box().image_rendering.to_layout(),
             })));
         });
     }
@@ -1581,7 +1581,7 @@ impl FragmentDisplayListBuilding for Fragment {
         display_list_section: DisplayListSection,
         clip: Rect<Au>,
     ) {
-        if self.style().get_inheritedbox().visibility != Visibility::Visible {
+        if self.style().get_inherited_box().visibility != Visibility::Visible {
             return;
         }
 
@@ -1744,7 +1744,7 @@ impl FragmentDisplayListBuilding for Fragment {
                     state,
                     &text_fragment,
                     stacking_relative_content_box,
-                    &self.style.get_inheritedtext().text_shadow.0,
+                    &self.style.get_inherited_text().text_shadow.0,
                     clip,
                 );
 
@@ -1765,7 +1765,7 @@ impl FragmentDisplayListBuilding for Fragment {
                     state,
                     &text_fragment,
                     stacking_relative_content_box,
-                    &self.style.get_inheritedtext().text_shadow.0,
+                    &self.style.get_inherited_text().text_shadow.0,
                     clip,
                 );
 
@@ -1837,7 +1837,7 @@ impl FragmentDisplayListBuilding for Fragment {
                             stretch_size: stacking_relative_content_box.size.to_layout(),
                             tile_spacing: LayoutSize::zero(),
                             image_rendering: self.style
-                                .get_inheritedbox()
+                                .get_inherited_box()
                                 .image_rendering
                                 .to_layout(),
                         })));
@@ -2005,7 +2005,7 @@ impl FragmentDisplayListBuilding for Fragment {
         }
 
         // Create display items for text decorations.
-        let text_decorations = self.style().get_inheritedtext().text_decorations_in_effect;
+        let text_decorations = self.style().get_inherited_text().text_decorations_in_effect;
 
         let logical_stacking_relative_content_box = LogicalRect::from_physical(
             self.style.writing_mode,
@@ -3048,8 +3048,8 @@ impl ComputedValuesCursorUtility for ComputedValues {
     #[inline]
     fn get_cursor(&self, default_cursor: CursorKind) -> Option<CursorKind> {
         match (
-            self.get_inheritedui().pointer_events,
-            &self.get_inheritedui().cursor,
+            self.get_inherited_ui().pointer_events,
+            &self.get_inherited_ui().cursor,
         ) {
             (PointerEvents::None, _) => None,
             (
diff --git a/components/layout/flex.rs b/components/layout/flex.rs
index 42ed7910b8d..2864c922874 100644
--- a/components/layout/flex.rs
+++ b/components/layout/flex.rs
@@ -561,7 +561,7 @@ impl FlexFlow {
                                     .explicit_block_size(parent_container_size)
                                     .map(|x| max(x - box_border, Au(0)));
         let containing_block_text_align =
-            self.block_flow.fragment.style().get_inheritedtext().text_align;
+            self.block_flow.fragment.style().get_inherited_text().text_align;
 
         while let Some(mut line) = self.get_flex_line(inline_size) {
             let items = &mut self.items[line.range.clone()];
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index 38ea9d03b93..b7b3ac07d64 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -818,7 +818,7 @@ impl Fragment {
             SpecificFragmentInfo::TableCell => {
                 let base_quantities = QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_PADDING |
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -828,7 +828,7 @@ impl Fragment {
             SpecificFragmentInfo::TableWrapper => {
                 let base_quantities = QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_MARGINS |
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -838,7 +838,7 @@ impl Fragment {
             SpecificFragmentInfo::TableRow => {
                 let base_quantities =
                     QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_SPECIFIED;
-                if self.style.get_inheritedtable().border_collapse ==
+                if self.style.get_inherited_table().border_collapse ==
                         BorderCollapse::Separate {
                     base_quantities | QuantitiesIncludedInIntrinsicInlineSizes::INTRINSIC_INLINE_SIZE_INCLUDES_BORDER
                 } else {
@@ -1272,7 +1272,7 @@ impl Fragment {
     pub fn compute_border_and_padding(&mut self,
                                       containing_block_inline_size: Au) {
         // Compute border.
-        let border = match self.style.get_inheritedtable().border_collapse {
+        let border = match self.style.get_inherited_table().border_collapse {
             BorderCollapse::Separate => self.border_width(),
             BorderCollapse::Collapse => LogicalMargin::zero(self.style.writing_mode),
         };
@@ -1377,7 +1377,7 @@ impl Fragment {
     }
 
     pub fn white_space(&self) -> WhiteSpace {
-        self.style().get_inheritedtext().white_space
+        self.style().get_inherited_text().white_space
     }
 
     pub fn color(&self) -> Color {
@@ -1625,12 +1625,12 @@ impl Fragment {
         let mut flags = SplitOptions::empty();
         if starts_line {
             flags.insert(SplitOptions::STARTS_LINE);
-            if self.style().get_inheritedtext().overflow_wrap == OverflowWrap::BreakWord {
+            if self.style().get_inherited_text().overflow_wrap == OverflowWrap::BreakWord {
                 flags.insert(SplitOptions::RETRY_AT_CHARACTER_BOUNDARIES)
             }
         }
 
-        match self.style().get_inheritedtext().word_break {
+        match self.style().get_inherited_text().word_break {
             WordBreak::Normal | WordBreak::KeepAll => {
                 // Break at normal word boundaries. keep-all forbids soft wrap opportunities.
                 let natural_word_breaking_strategy =
diff --git a/components/layout/inline.rs b/components/layout/inline.rs
index 83961219e37..58d6a498457 100644
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@@ -934,7 +934,7 @@ impl InlineFlow {
         if fragments.fragments.is_empty() {
             return
         }
-        let text_justify = fragments.fragments[0].style().get_inheritedtext().text_justify;
+        let text_justify = fragments.fragments[0].style().get_inherited_text().text_justify;
 
         // Translate `left` and `right` to logical directions.
         let is_ltr = fragments.fragments[0].style().writing_mode.is_bidi_ltr();
@@ -1341,7 +1341,7 @@ impl Flow for InlineFlow {
         let mut intrinsic_sizes_for_nonbroken_run = IntrinsicISizesContribution::new();
         for fragment in &mut self.fragments.fragments {
             let intrinsic_sizes_for_fragment = fragment.compute_intrinsic_inline_sizes().finish();
-            match fragment.style.get_inheritedtext().white_space {
+            match fragment.style.get_inherited_text().white_space {
                 WhiteSpace::Nowrap => {
                     intrinsic_sizes_for_nonbroken_run.union_nonbreaking_inline(
                         &intrinsic_sizes_for_fragment)
diff --git a/components/layout/query.rs b/components/layout/query.rs
index b52d415939f..408e220dfe4 100644
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@@ -959,7 +959,7 @@ fn inner_text_collection_steps<N: LayoutNode>(node: N,
         };
 
         // Step 2.
-        if style.get_inheritedbox().visibility != Visibility::Visible {
+        if style.get_inherited_box().visibility != Visibility::Visible {
             continue;
         }
 
diff --git a/components/layout/table.rs b/components/layout/table.rs
index a258a570692..658a39d8e21 100644
--- a/components/layout/table.rs
+++ b/components/layout/table.rs
@@ -191,8 +191,8 @@ impl TableFlow {
     /// Returns the effective spacing per cell, taking the value of `border-collapse` into account.
     pub fn spacing(&self) -> border_spacing::T {
         let style = self.block_flow.fragment.style();
-        match style.get_inheritedtable().border_collapse {
-            border_collapse::T::Separate => style.get_inheritedtable().border_spacing,
+        match style.get_inherited_table().border_collapse {
+            border_collapse::T::Separate => style.get_inherited_table().border_spacing,
             border_collapse::T::Collapse => border_spacing::T::zero(),
         }
     }
@@ -298,7 +298,7 @@ impl Flow for TableFlow {
         let collapsing_borders = self.block_flow
                                      .fragment
                                      .style
-                                     .get_inheritedtable()
+                                     .get_inherited_table()
                                      .border_collapse == border_collapse::T::Collapse;
         let table_inline_collapsed_borders = if collapsing_borders {
             Some(TableInlineCollapsedBorders {
@@ -522,7 +522,7 @@ impl Flow for TableFlow {
         let border_painting_mode = match self.block_flow
                                              .fragment
                                              .style
-                                             .get_inheritedtable()
+                                             .get_inherited_table()
                                              .border_collapse {
             border_collapse::T::Separate => BorderPaintingMode::Separate,
             border_collapse::T::Collapse => BorderPaintingMode::Hidden,
@@ -771,12 +771,12 @@ pub trait TableLikeFlow {
 impl TableLikeFlow for BlockFlow {
     fn assign_block_size_for_table_like_flow(&mut self, block_direction_spacing: Au,
                                              layout_context: &LayoutContext) {
-        debug_assert!(self.fragment.style.get_inheritedtable().border_collapse ==
+        debug_assert!(self.fragment.style.get_inherited_table().border_collapse ==
                       border_collapse::T::Separate || block_direction_spacing == Au(0));
 
         fn border_spacing_for_row(fragment: &Fragment, row: &TableRowFlow,
                                   block_direction_spacing: Au) -> Au {
-            match fragment.style.get_inheritedtable().border_collapse {
+            match fragment.style.get_inherited_table().border_collapse {
                 border_collapse::T::Separate => block_direction_spacing,
                 border_collapse::T::Collapse => {
                     row.collapsed_border_spacing.block_start
@@ -1204,13 +1204,13 @@ impl<'table> TableCellStyleInfo<'table> {
         use style::computed_values::visibility::T as Visibility;
 
         if !self.cell.visible || self.cell.block_flow.fragment.style()
-                                     .get_inheritedbox().visibility != Visibility::Visible {
+                                     .get_inherited_box().visibility != Visibility::Visible {
             return
         }
         let border_painting_mode = match self.cell.block_flow
                                              .fragment
                                              .style
-                                             .get_inheritedtable()
+                                             .get_inherited_table()
                                              .border_collapse {
             border_collapse::T::Separate => BorderPaintingMode::Separate,
             border_collapse::T::Collapse => BorderPaintingMode::Collapse(&self.cell.collapsed_borders),
diff --git a/components/layout/table_row.rs b/components/layout/table_row.rs
index 933d3be632e..ffecce5d6c7 100644
--- a/components/layout/table_row.rs
+++ b/components/layout/table_row.rs
@@ -353,7 +353,7 @@ impl Flow for TableRowFlow {
         let collapsing_borders = self.block_flow
                                      .fragment
                                      .style()
-                                     .get_inheritedtable()
+                                     .get_inherited_table()
                                      .border_collapse == BorderCollapse::Collapse;
         let row_style = &*self.block_flow.fragment.style;
         self.preliminary_collapsed_borders.reset(
@@ -500,7 +500,7 @@ impl Flow for TableRowFlow {
 
         // Set up border collapse info.
         let border_collapse_info =
-            match self.block_flow.fragment.style().get_inheritedtable().border_collapse {
+            match self.block_flow.fragment.style().get_inherited_table().border_collapse {
                 BorderCollapse::Collapse => {
                     Some(BorderCollapseInfoForChildTableCell {
                         collapsed_borders_for_row: &self.final_collapsed_borders,
diff --git a/components/layout/table_rowgroup.rs b/components/layout/table_rowgroup.rs
index 85bccb18ade..cac1657bd43 100644
--- a/components/layout/table_rowgroup.rs
+++ b/components/layout/table_rowgroup.rs
@@ -130,7 +130,7 @@ impl Flow for TableRowGroupFlow {
         let (inline_start_content_edge, inline_end_content_edge) = (Au(0), Au(0));
         let content_inline_size = containing_block_inline_size;
 
-        let border_collapse = self.block_flow.fragment.style.get_inheritedtable().border_collapse;
+        let border_collapse = self.block_flow.fragment.style.get_inherited_table().border_collapse;
         let inline_size_computer = InternalTable;
         inline_size_computer.compute_used_inline_size(&mut self.block_flow,
                                                       shared_context,
diff --git a/components/layout/text.rs b/components/layout/text.rs
index 15fecd3f7d1..ac93eaed03f 100644
--- a/components/layout/text.rs
+++ b/components/layout/text.rs
@@ -170,7 +170,7 @@ impl TextRunScanner {
             {
                 let in_fragment = self.clump.front().unwrap();
                 let font_style = in_fragment.style().clone_font();
-                let inherited_text_style = in_fragment.style().get_inheritedtext();
+                let inherited_text_style = in_fragment.style().get_inherited_text();
                 font_group = font_context.font_group(font_style);
                 compression = match in_fragment.white_space() {
                     WhiteSpace::Normal |
@@ -477,7 +477,7 @@ pub fn font_metrics_for_style(mut font_context: &mut LayoutFontContext, style: :
 /// Returns the line block-size needed by the given computed style and font size.
 pub fn line_height_from_style(style: &ComputedValues, metrics: &FontMetrics) -> Au {
     let font_size = style.get_font().font_size.size();
-    match style.get_inheritedtext().line_height {
+    match style.get_inherited_text().line_height {
         LineHeight::Normal => Au::from(metrics.line_gap),
         LineHeight::Number(l) => font_size.scale_by(l.0),
         LineHeight::Length(l) => Au::from(l)
diff --git a/components/layout_thread/dom_wrapper.rs b/components/layout_thread/dom_wrapper.rs
index 309ddaf7e93..89a21ec64d5 100644
--- a/components/layout_thread/dom_wrapper.rs
+++ b/components/layout_thread/dom_wrapper.rs
@@ -979,7 +979,7 @@ impl<'ln> ThreadSafeLayoutNode for ServoThreadSafeLayoutNode<'ln> {
             //
             // If you implement other values for this property, you will almost certainly
             // want to update this check.
-            !self.style(context).get_inheritedtext().white_space.preserve_newlines()
+            !self.style(context).get_inherited_text().white_space.preserve_newlines()
         }
     }
 
diff --git a/components/layout_thread/lib.rs b/components/layout_thread/lib.rs
index f0383e871fa..3c39b95a28b 100644
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@@ -128,7 +128,7 @@ use style::context::{QuirksMode, RegisteredSpeculativePainter, RegisteredSpecula
 use style::context::{SharedStyleContext, StyleSystemOptions, ThreadLocalStyleContextCreationInfo};
 use style::dom::{ShowSubtree, ShowSubtreeDataAndPrimaryValues, TElement, TNode};
 use style::driver;
-use style::error_reporting::{NullReporter, RustLogReporter};
+use style::error_reporting::RustLogReporter;
 use style::invalidation::element::restyle_hints::RestyleHint;
 use style::logical_geometry::LogicalPoint;
 use style::media_queries::{Device, MediaList, MediaType};
@@ -1754,7 +1754,7 @@ fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
             MediaList::empty(),
             shared_lock.clone(),
             None,
-            &NullReporter,
+            None,
             QuirksMode::NoQuirks,
         ))))
     }
@@ -1782,7 +1782,7 @@ fn get_ua_stylesheets() -> Result<UserAgentStylesheets, &'static str> {
                 MediaList::empty(),
                 shared_lock.clone(),
                 None,
-                &RustLogReporter,
+                Some(&RustLogReporter),
                 QuirksMode::NoQuirks,
             )))
         );
diff --git a/components/script/dom/css.rs b/components/script/dom/css.rs
index 4b67f516e83..d642b44a19f 100644
--- a/components/script/dom/css.rs
+++ b/components/script/dom/css.rs
@@ -42,7 +42,8 @@ impl CSS {
             &url,
             Some(CssRuleType::Style),
             ParsingMode::DEFAULT,
-            QuirksMode::NoQuirks
+            QuirksMode::NoQuirks,
+            None,
         );
         decl.eval(&context)
     }
@@ -58,7 +59,8 @@ impl CSS {
                 &url,
                 Some(CssRuleType::Style),
                 ParsingMode::DEFAULT,
-                QuirksMode::NoQuirks
+                QuirksMode::NoQuirks,
+                None,
             );
             cond.eval(&context)
         } else {
diff --git a/components/script/dom/cssmediarule.rs b/components/script/dom/cssmediarule.rs
index 0ecdf71a314..23f3c46a251 100644
--- a/components/script/dom/cssmediarule.rs
+++ b/components/script/dom/cssmediarule.rs
@@ -75,15 +75,15 @@ impl CSSMediaRule {
         let window = global.as_window();
         let url = window.get_url();
         let quirks_mode = window.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
-
-        let new_medialist = StyleMediaList::parse(
-            &context,
-            &mut input,
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             window.css_error_reporter(),
         );
+
+        let new_medialist = StyleMediaList::parse(&context, &mut input);
         let mut guard = self.cssconditionrule.shared_lock().write();
 
         // Clone an Arc because we can’t borrow `guard` twice at the same time.
diff --git a/components/script/dom/cssstyledeclaration.rs b/components/script/dom/cssstyledeclaration.rs
index e3a4a20d380..9f6c97dbc7d 100644
--- a/components/script/dom/cssstyledeclaration.rs
+++ b/components/script/dom/cssstyledeclaration.rs
@@ -181,6 +181,19 @@ macro_rules! css_properties(
     );
 );
 
+fn remove_property(
+    decls: &mut PropertyDeclarationBlock,
+    id: &PropertyId,
+) -> bool {
+    let first_declaration = decls.first_declaration_to_remove(id);
+    let first_declaration = match first_declaration {
+        Some(i) => i,
+        None => return false,
+    };
+    decls.remove_property(id, first_declaration);
+    true
+}
+
 impl CSSStyleDeclaration {
     #[allow(unrooted_must_root)]
     pub fn new_inherited(owner: CSSStyleOwner,
@@ -253,7 +266,7 @@ impl CSSStyleDeclaration {
         self.owner.mutate_associated_block(|pdb, changed| {
             if value.is_empty() {
                 // Step 3
-                *changed = pdb.remove_property(&id, |_| {});
+                *changed = remove_property(pdb, &id);
                 return Ok(());
             }
 
@@ -365,7 +378,7 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
         let mut string = String::new();
         self.owner.mutate_associated_block(|pdb, changed| {
             pdb.property_value_to_css(&id, &mut string).unwrap();
-            *changed = pdb.remove_property(&id, |_| {});
+            *changed = remove_property(pdb, &id);
         });
 
         // Step 6
diff --git a/components/script/dom/csssupportsrule.rs b/components/script/dom/csssupportsrule.rs
index 68d02aa241a..a96cd706b86 100644
--- a/components/script/dom/csssupportsrule.rs
+++ b/components/script/dom/csssupportsrule.rs
@@ -63,9 +63,13 @@ impl CSSSupportsRule {
             let win = global.as_window();
             let url = win.Document().url();
             let quirks_mode = win.Document().quirks_mode();
-            let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Supports),
-                                                       ParsingMode::DEFAULT,
-                                                       quirks_mode);
+            let context = ParserContext::new_for_cssom(
+                &url,
+                Some(CssRuleType::Supports),
+                ParsingMode::DEFAULT,
+                quirks_mode,
+                None,
+            );
             let enabled = cond.eval(&context);
             let mut guard = self.cssconditionrule.shared_lock().write();
             let rule = self.supportsrule.write_with(&mut guard);
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 9e048161633..26c59bdb8ec 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -127,6 +127,7 @@ use std::cell::{Cell, Ref, RefMut};
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::default::Default;
+use std::fmt;
 use std::mem;
 use std::ptr::NonNull;
 use std::rc::Rc;
@@ -213,6 +214,12 @@ struct StyleSheetInDocument {
     owner: Dom<Element>,
 }
 
+impl fmt::Debug for StyleSheetInDocument {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        self.sheet.fmt(formatter)
+    }
+}
+
 impl PartialEq for StyleSheetInDocument {
     fn eq(&self, other: &Self) -> bool {
         Arc::ptr_eq(&self.sheet, &other.sheet)
diff --git a/components/script/dom/htmlimageelement.rs b/components/script/dom/htmlimageelement.rs
index 8206af23e3e..61acecda71d 100644
--- a/components/script/dom/htmlimageelement.rs
+++ b/components/script/dom/htmlimageelement.rs
@@ -770,10 +770,13 @@ pub fn parse_a_sizes_attribute(input: DOMString, width: Option<u32>) -> Vec<Size
         }
         let mut input = ParserInput::new(&trimmed);
         let url = ServoUrl::parse("about:blank").unwrap();
-        let context = ParserContext::new_for_cssom(&url,
-                                                   None,
-                                                   ParsingMode::empty(),
-                                                   QuirksMode::NoQuirks);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            None,
+            ParsingMode::empty(),
+            QuirksMode::NoQuirks,
+            None,
+        );
         let mut parser = Parser::new(&mut input);
         let length = parser.try(|i| Length::parse_non_negative(&context, i));
         match length {
diff --git a/components/script/dom/htmllinkelement.rs b/components/script/dom/htmllinkelement.rs
index ab84906d223..a86789dcd71 100644
--- a/components/script/dom/htmllinkelement.rs
+++ b/components/script/dom/htmllinkelement.rs
@@ -277,6 +277,7 @@ impl HTMLLinkElement {
         let mut input = ParserInput::new(&mq_str);
         let mut css_parser = CssParser::new(&mut input);
         let doc_url = document.url();
+        let window = document.window();
         // FIXME(emilio): This looks somewhat fishy, since we use the context
         // only to parse the media query list, CssRuleType::Media doesn't make
         // much sense.
@@ -285,13 +286,9 @@ impl HTMLLinkElement {
             Some(CssRuleType::Media),
             ParsingMode::DEFAULT,
             document.quirks_mode(),
-        );
-        let window = document.window();
-        let media = MediaList::parse(
-            &context,
-            &mut css_parser,
             window.css_error_reporter(),
         );
+        let media = MediaList::parse(&context, &mut css_parser);
 
         let im_attribute = element.get_attribute(&ns!(), &local_name!("integrity"));
         let integrity_val = im_attribute.r().map(|a| a.value());
diff --git a/components/script/dom/htmlstyleelement.rs b/components/script/dom/htmlstyleelement.rs
index 6778af92218..82da9ba6180 100644
--- a/components/script/dom/htmlstyleelement.rs
+++ b/components/script/dom/htmlstyleelement.rs
@@ -84,25 +84,32 @@ impl HTMLStyleElement {
 
         let data = node.GetTextContent().expect("Element.textContent must be a string");
         let url = window.get_url();
-        let context = CssParserContext::new_for_cssom(&url,
-                                                      Some(CssRuleType::Media),
-                                                      ParsingMode::DEFAULT,
-                                                      doc.quirks_mode());
+        let css_error_reporter = window.css_error_reporter();
+        let context = CssParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            doc.quirks_mode(),
+            css_error_reporter,
+        );
         let shared_lock = node.owner_doc().style_shared_lock().clone();
         let mut input = ParserInput::new(&mq_str);
-        let css_error_reporter = window.css_error_reporter();
         let mq = Arc::new(shared_lock.wrap(MediaList::parse(
             &context,
             &mut CssParser::new(&mut input),
-            css_error_reporter),
-        ));
+        )));
         let loader = StylesheetLoader::for_element(self.upcast());
-        let sheet = Stylesheet::from_str(&data, window.get_url(),
-                                         Origin::Author, mq,
-                                         shared_lock, Some(&loader),
-                                         css_error_reporter,
-                                         doc.quirks_mode(),
-                                         self.line_number as u32);
+        let sheet = Stylesheet::from_str(
+            &data,
+            window.get_url(),
+            Origin::Author,
+            mq,
+            shared_lock,
+            Some(&loader),
+            css_error_reporter,
+            doc.quirks_mode(),
+            self.line_number as u32,
+        );
 
         let sheet = Arc::new(sheet);
 
diff --git a/components/script/dom/medialist.rs b/components/script/dom/medialist.rs
index 2f5b33c1016..d43f6d3a710 100644
--- a/components/script/dom/medialist.rs
+++ b/components/script/dom/medialist.rs
@@ -77,14 +77,14 @@ impl MediaListMethods for MediaList {
         let window = global.as_window();
         let url = window.get_url();
         let quirks_mode = window.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
-        *media_queries = StyleMediaList::parse(
-            &context,
-            &mut parser,
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             window.css_error_reporter(),
         );
+        *media_queries = StyleMediaList::parse(&context, &mut parser);
     }
 
     // https://drafts.csswg.org/cssom/#dom-medialist-length
@@ -117,9 +117,13 @@ impl MediaListMethods for MediaList {
         let win = global.as_window();
         let url = win.get_url();
         let quirks_mode = win.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
+            win.css_error_reporter(),
+        );
         let m = MediaQuery::parse(&context, &mut parser);
         // Step 2
         if let Err(_) = m {
@@ -146,9 +150,13 @@ impl MediaListMethods for MediaList {
         let win = global.as_window();
         let url = win.get_url();
         let quirks_mode = win.Document().quirks_mode();
-        let context = ParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                   ParsingMode::DEFAULT,
-                                                   quirks_mode);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
+            win.css_error_reporter(),
+        );
         let m = MediaQuery::parse(&context, &mut parser);
         // Step 2
         if let Err(_) = m {
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 0f259dd2ea7..b536f28345f 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -100,6 +100,7 @@ use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{Sender, channel};
 use std::sync::mpsc::TryRecvError::{Disconnected, Empty};
+use style::error_reporting::ParseErrorReporter;
 use style::media_queries;
 use style::parser::ParserContext as CssParserContext;
 use style::properties::{ComputedValues, PropertyId};
@@ -389,8 +390,8 @@ impl Window {
          &self.bluetooth_extra_permission_data
     }
 
-    pub fn css_error_reporter(&self) -> &CSSErrorReporter {
-        &self.error_reporter
+    pub fn css_error_reporter(&self) -> Option<&ParseErrorReporter> {
+        Some(&self.error_reporter)
     }
 
     /// Sets a new list of scroll offsets.
@@ -1017,14 +1018,15 @@ impl WindowMethods for Window {
         let mut parser = Parser::new(&mut input);
         let url = self.get_url();
         let quirks_mode = self.Document().quirks_mode();
-        let context = CssParserContext::new_for_cssom(&url, Some(CssRuleType::Media),
-                                                      ParsingMode::DEFAULT,
-                                                      quirks_mode);
-        let media_query_list = media_queries::MediaList::parse(
-            &context,
-            &mut parser,
+        let context = CssParserContext::new_for_cssom(
+            &url,
+            Some(CssRuleType::Media),
+            ParsingMode::DEFAULT,
+            quirks_mode,
             self.css_error_reporter(),
         );
+        let media_query_list =
+            media_queries::MediaList::parse(&context, &mut parser);
         let document = self.Document();
         let mql = MediaQueryList::new(&document, media_query_list);
         self.media_query_lists.push(&*mql);