--- a/layout/style/nsCSSPropList.h
+++ b/layout/style/nsCSSPropList.h
@@ -175,75 +175,75 @@ CSS_PROP_SHORTHAND(
     animation,
     Animation,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     animation-delay,
     animation_delay,
     AnimationDelay,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_TIME, // used by list parsing
     nullptr)
 CSS_PROP_(
     animation-direction,
     animation_direction,
     AnimationDirection,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kAnimationDirectionKTable)
 CSS_PROP_(
     animation-duration,
     animation_duration,
     AnimationDuration,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_TIME | VARIANT_NONNEGATIVE_DIMENSION, // used by list parsing
     nullptr)
 CSS_PROP_(
     animation-fill-mode,
     animation_fill_mode,
     AnimationFillMode,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kAnimationFillModeKTable)
 CSS_PROP_(
     animation-iteration-count,
     animation_iteration_count,
     AnimationIterationCount,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD | VARIANT_NUMBER, // used by list parsing
     kAnimationIterationCountKTable)
 CSS_PROP_(
     animation-name,
     animation_name,
     AnimationName,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     // FIXME: The spec should say something about 'inherit' and 'initial'
     // not being allowed.
     VARIANT_NONE | VARIANT_IDENTIFIER_NO_INHERIT | VARIANT_STRING, // used by list parsing
     nullptr)
 CSS_PROP_(
     animation-play-state,
     animation_play_state,
     AnimationPlayState,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kAnimationPlayStateKTable)
 CSS_PROP_(
     animation-timing-function,
     animation_timing_function,
     AnimationTimingFunction,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD | VARIANT_TIMING_FUNCTION, // used by list parsing
     kTransitionTimingFunctionKTable)
 CSS_PROP_(
     -moz-appearance,
     _moz_appearance,
     CSS_PROP_DOMPROP_PREFIXED(Appearance),
     0,
@@ -263,99 +263,95 @@ CSS_PROP_SHORTHAND(
     background,
     Background,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     background-attachment,
     background_attachment,
     BackgroundAttachment,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kImageLayerAttachmentKTable)
 CSS_PROP_(
     background-blend-mode,
     background_blend_mode,
     BackgroundBlendMode,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "layout.css.background-blend-mode.enabled",
     VARIANT_KEYWORD, // used by list parsing
     kBlendModeKTable)
 CSS_PROP_(
     background-clip,
     background_clip,
     BackgroundClip,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kBackgroundClipKTable)
 CSS_PROP_(
     background-color,
     background_color,
     BackgroundColor,
     0,
     "",
     VARIANT_HC,
     nullptr)
 CSS_PROP_(
     background-image,
     background_image,
     BackgroundImage,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_IMAGE, // used by list parsing
     nullptr)
 CSS_PROP_(
     background-origin,
     background_origin,
     BackgroundOrigin,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kBackgroundOriginKTable)
 CSS_PROP_SHORTHAND(
     background-position,
     background_position,
     BackgroundPosition,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     background-position-x,
     background_position_x,
     BackgroundPositionX,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerPositionKTable)
 CSS_PROP_(
     background-position-y,
     background_position_y,
     BackgroundPositionY,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerPositionKTable)
 CSS_PROP_(
     background-repeat,
     background_repeat,
     BackgroundRepeat,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kImageLayerRepeatKTable)
 CSS_PROP_(
     background-size,
     background_size,
     BackgroundSize,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerSizeKTable)
 CSS_PROP_(
     -moz-binding,
     _moz_binding,
     CSS_PROP_DOMPROP_PREFIXED(Binding),
     0,
@@ -797,18 +793,17 @@ CSS_PROP_(
     0,
     "",
     VARIANT_HK,
     kBoxPackKTable) // XXX bug 3935
 CSS_PROP_(
     box-shadow,
     box_shadow,
     BoxShadow,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
         // NOTE: some components must be nonnegative
     "",
     VARIANT_COLOR | VARIANT_LENGTH | VARIANT_CALC | VARIANT_INHERIT | VARIANT_NONE,
     kBoxShadowTypeKTable)
 CSS_PROP_(
     box-sizing,
     box_sizing,
     BoxSizing,
@@ -991,17 +986,16 @@ CSS_PROP_(
     kContentKTable)
 #ifndef CSS_PROP_LIST_EXCLUDE_INTERNAL
 CSS_PROP_(
     // Only intended to be used internally by Mozilla, so prefixed.
     -moz-context-properties,
     _moz_context_properties,
     CSS_PROP_DOMPROP_PREFIXED(ContextProperties),
     CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS |
         CSS_PROPERTY_INTERNAL,
     "",
     0,
     nullptr)
 CSS_PROP_(
     -moz-control-character-visibility,
     _moz_control_character_visibility,
     CSS_PROP_DOMPROP_PREFIXED(ControlCharacterVisibility),
@@ -1025,18 +1019,17 @@ CSS_PROP_(
     CSS_PROPERTY_PARSE_FUNCTION,
     "",
     VARIANT_INHERIT | VARIANT_NONE,
     nullptr) // XXX bug 137285
 CSS_PROP_(
     cursor,
     cursor,
     Cursor,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kCursorKTable)
 #ifndef CSS_PROP_LIST_ONLY_COMPONENTS_OF_ALL_SHORTHAND
 CSS_PROP_(
     direction,
     direction,
     Direction,
@@ -1344,18 +1337,17 @@ CSS_PROP_(
     0,
     "",
     VARIANT_HMK,
     kFontVariantPositionKTable)
 CSS_PROP_(
     font-variation-settings,
     font_variation_settings,
     FontVariationSettings,
-    CSS_PROPERTY_VALUE_PARSER_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_VALUE_PARSER_FUNCTION,
     "layout.css.font-variations.enabled",
     0,
     nullptr)
 CSS_PROP_(
     font-weight,
     font_weight,
     FontWeight,
     CSS_PROPERTY_VALUE_PARSER_FUNCTION,
@@ -1782,91 +1774,87 @@ CSS_PROP_SHORTHAND(
     mask,
     Mask,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     mask-clip,
     mask_clip,
     MaskClip,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kMaskClipKTable)
 CSS_PROP_(
     mask-composite,
     mask_composite,
     MaskComposite,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kImageLayerCompositeKTable)
 CSS_PROP_(
     mask-image,
     mask_image,
     MaskImage,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_IMAGE, // used by list parsing
     nullptr)
 CSS_PROP_(
     mask-mode,
     mask_mode,
     MaskMode,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kImageLayerModeKTable)
 CSS_PROP_(
     mask-origin,
     mask_origin,
     MaskOrigin,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kMaskOriginKTable)
 CSS_PROP_SHORTHAND(
     mask-position,
     mask_position,
     MaskPosition,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     mask-position-x,
     mask_position_x,
     MaskPositionX,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerPositionKTable)
 CSS_PROP_(
     mask-position-y,
     mask_position_y,
     MaskPositionY,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerPositionKTable)
 CSS_PROP_(
     mask-repeat,
     mask_repeat,
     MaskRepeat,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     VARIANT_KEYWORD, // used by list parsing
     kImageLayerRepeatKTable)
 CSS_PROP_(
     mask-size,
     mask_size,
     MaskSize,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kImageLayerSizeKTable)
 CSS_PROP_(
     mask-type,
     mask_type,
     MaskType,
     0,
@@ -2463,18 +2451,17 @@ CSS_PROP_(
     0,
     "layout.css.scroll-behavior.property-enabled",
     VARIANT_HK,
     kScrollBehaviorKTable)
 CSS_PROP_(
     scroll-snap-coordinate,
     scroll_snap_coordinate,
     ScrollSnapCoordinate,
-    CSS_PROPERTY_VALUE_PARSER_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_VALUE_PARSER_FUNCTION,
     "layout.css.scroll-snap.enabled",
     0,
     kImageLayerPositionKTable)
 CSS_PROP_(
     scroll-snap-destination,
     scroll_snap_destination,
     ScrollSnapDestination,
     CSS_PROPERTY_VALUE_PARSER_FUNCTION,
@@ -2587,18 +2574,17 @@ CSS_PROP_(
     CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     kContextPatternKTable)
 CSS_PROP_(
     stroke-dasharray,
     stroke_dasharray,
     StrokeDasharray,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
         // NOTE: Internal values have range restrictions.
     "",
     0,
     kStrokeContextValueKTable)
 CSS_PROP_(
     stroke-dashoffset,
     stroke_dashoffset,
     StrokeDashoffset,
@@ -2803,18 +2789,17 @@ CSS_PROP_(
     0,
     "",
     VARIANT_HK,
     kTextRenderingKTable)
 CSS_PROP_(
     text-shadow,
     text_shadow,
     TextShadow,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
         // NOTE: some components must be nonnegative
     "",
     VARIANT_COLOR | VARIANT_LENGTH | VARIANT_CALC | VARIANT_INHERIT | VARIANT_NONE,
     nullptr)
 CSS_PROP_(
     -moz-text-size-adjust,
     _moz_text_size_adjust,
     CSS_PROP_DOMPROP_PREFIXED(TextSizeAdjust),
@@ -2932,42 +2917,41 @@ CSS_PROP_SHORTHAND(
     transition,
     Transition,
     CSS_PROPERTY_PARSE_FUNCTION,
     "")
 CSS_PROP_(
     transition-delay,
     transition_delay,
     TransitionDelay,
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_TIME, // used by list parsing
     nullptr)
 CSS_PROP_(
     transition-duration,
     transition_duration,
     TransitionDuration,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_TIME | VARIANT_NONNEGATIVE_DIMENSION, // used by list parsing
     nullptr)
 CSS_PROP_(
     transition-property,
     transition_property,
     TransitionProperty,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     VARIANT_IDENTIFIER | VARIANT_NONE | VARIANT_ALL, // used only in shorthand
     nullptr)
 CSS_PROP_(
     transition-timing-function,
     transition_timing_function,
     TransitionTimingFunction,
-    CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    0,
     "",
     VARIANT_KEYWORD | VARIANT_TIMING_FUNCTION, // used by list parsing
     kTransitionTimingFunctionKTable)
 CSS_PROP_(
     translate,
     translate,
     Translate,
     CSS_PROPERTY_PARSE_FUNCTION |
@@ -3059,35 +3043,34 @@ CSS_PROP_(
     CSS_PROPERTY_GETCS_NEEDS_LAYOUT_FLUSH,
     "",
     VARIANT_AHKLP | VARIANT_CALC,
     kWidthKTable)
 CSS_PROP_(
     will-change,
     will_change,
     WillChange,
-    CSS_PROPERTY_PARSE_FUNCTION |
-        CSS_PROPERTY_VALUE_LIST_USES_COMMAS,
+    CSS_PROPERTY_PARSE_FUNCTION,
     "",
     0,
     nullptr)
 CSS_PROP_(
     -moz-window-dragging,
     _moz_window_dragging,
     CSS_PROP_DOMPROP_PREFIXED(WindowDragging),
     0,
     "",
     VARIANT_HK,
     kWindowDraggingKTable)
 #ifndef CSS_PROP_LIST_EXCLUDE_INTERNAL
 CSS_PROP_(
     -moz-window-opacity,
     _moz_window_opacity,
     CSS_PROP_DOMPROP_PREFIXED(WindowOpacity),
-    CSS_PROPERTY_INTERNAL | 0,
+    CSS_PROPERTY_INTERNAL,
     "",
     VARIANT_HN,
     nullptr)
 CSS_PROP_(
     -moz-window-shadow,
     _moz_window_shadow,
     CSS_PROP_DOMPROP_PREFIXED(WindowShadow),
     CSS_PROPERTY_INTERNAL |

--- a/layout/style/nsCSSProps.h
+++ b/layout/style/nsCSSProps.h
@@ -119,18 +119,16 @@
 #define VARIANT_LPCALC (VARIANT_LCALC | VARIANT_PERCENT)
 #define VARIANT_LNCALC (VARIANT_LCALC | VARIANT_NUMBER)
 #define VARIANT_LPNCALC (VARIANT_LNCALC | VARIANT_PERCENT)
 #define VARIANT_IMAGE   (VARIANT_URL | VARIANT_NONE | VARIANT_GRADIENT | \
                         VARIANT_IMAGE_RECT | VARIANT_ELEMENT)
 
 // Flags for the kFlagsTable bitfield (flags_ in nsCSSPropList.h)
 
-#define CSS_PROPERTY_VALUE_LIST_USES_COMMAS       (1<<1) /* otherwise spaces */
-
 // Define what mechanism the CSS parser uses for parsing the property.
 // See CSSParserImpl::ParseProperty(nsCSSPropertyID).  Don't use 0 so that
 // we can verify that every property sets one of the values.
 #define CSS_PROPERTY_PARSE_PROPERTY_MASK          (7<<9)
 #define CSS_PROPERTY_PARSE_INACCESSIBLE           (1<<9)
 #define CSS_PROPERTY_PARSE_FUNCTION               (2<<9)
 
 // See CSSParserImpl::ParseSingleValueProperty and comment above