CSSValue Immediates: Change CSSValue to an object instead of a pointer

Source/core/css/ComputedStyleCSSValueMapping.cpp

Index: Source/core/css/ComputedStyleCSSValueMapping.cpp
diff --git a/Source/core/css/ComputedStyleCSSValueMapping.cpp b/Source/core/css/ComputedStyleCSSValueMapping.cpp
index 6e7bf2485fdd8e6e13ef455c9247cfe963628249..2ac64f2d3f48d421a42ddbddd210a2e0b9fb1159 100644
--- a/Source/core/css/ComputedStyleCSSValueMapping.cpp
+++ b/Source/core/css/ComputedStyleCSSValueMapping.cpp
@@ -108,7 +108,7 @@ PassRefPtrWillBeRawPtr<CSSPrimitiveValue> ComputedStyleCSSValueMapping::currentC
     return cssValuePool().createColorValue(color.resolve(style.color()).rgb());
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForFillSize(const FillSize& fillSize, const ComputedStyle& style)
+static CSSValue valueForFillSize(const FillSize& fillSize, const ComputedStyle& style)
 {
     if (fillSize.type == Contain)
         return cssValuePool().createIdentifierValue(CSSValueContain);
@@ -125,7 +125,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForFillSize(const FillSize& fillSiz
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForFillRepeat(EFillRepeat xRepeat, EFillRepeat yRepeat)
+static CSSValue valueForFillRepeat(EFillRepeat xRepeat, EFillRepeat yRepeat)
 {
     // For backwards compatibility, if both values are equal, just return one of them. And
     // if the two values are equivalent to repeat-x or repeat-y, just return the shorthand.
@@ -142,7 +142,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForFillRepeat(EFillRepeat xRepeat,
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForFillSourceType(EMaskSourceType type)
+static CSSValue valueForFillSourceType(EMaskSourceType type)
 {
     switch (type) {
     case MaskAlpha:
@@ -152,11 +152,10 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForFillSourceType(EMaskSourceType t
     }
 
     ASSERT_NOT_REACHED();
-
-    return nullptr;
+    return cssValuePool().createValue(CSSValueAlpha);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForPositionOffset(const ComputedStyle& style, CSSPropertyID propertyID, const LayoutObject* layoutObject)
+static CSSValue valueForPositionOffset(const ComputedStyle& style, CSSPropertyID propertyID, const LayoutObject* layoutObject)
 {
     Length offset;
     switch (propertyID) {
@@ -173,7 +172,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForPositionOffset(const ComputedSty
         offset = style.bottom();
         break;
     default:
-        return nullptr;
+        return cssValuePool().createIdentifierValue(CSSValueAuto);
     }
 
     if (offset.hasPercent() && layoutObject && layoutObject->isBox() && layoutObject->isPositioned()) {
@@ -312,7 +311,7 @@ static CSSValueID valueForRepeatRule(int rule)
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForNinePieceImageRepeat(const NinePieceImage& image)
+static CSSValue valueForNinePieceImageRepeat(const NinePieceImage& image)
 {
     RefPtrWillBeRawPtr<CSSPrimitiveValue> horizontalRepeat = nullptr;
     RefPtrWillBeRawPtr<CSSPrimitiveValue> verticalRepeat = nullptr;
@@ -325,13 +324,13 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForNinePieceImageRepeat(const NineP
     return cssValuePool().createValue(Pair::create(horizontalRepeat.release(), verticalRepeat.release(), Pair::DropIdenticalValues));
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForNinePieceImage(const NinePieceImage& image, const ComputedStyle& style)
+static CSSValue valueForNinePieceImage(const NinePieceImage& image, const ComputedStyle& style)
 {
     if (!image.hasImage())
         return cssValuePool().createIdentifierValue(CSSValueNone);
 
     // Image first.
-    RefPtrWillBeRawPtr<CSSValue> imageValue = nullptr;
+    NullableCSSValue imageValue;
     if (image.image())
         imageValue = image.image()->cssValue();
 
@@ -339,18 +338,18 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForNinePieceImage(const NinePieceIm
     RefPtrWillBeRawPtr<CSSBorderImageSliceValue> imageSlices = valueForNinePieceImageSlice(image);
 
     // Create the border area slices.
-    RefPtrWillBeRawPtr<CSSValue> borderSlices = valueForNinePieceImageQuad(image.borderSlices(), style);
+    CSSValue borderSlices = valueForNinePieceImageQuad(image.borderSlices(), style);
 
     // Create the border outset.
-    RefPtrWillBeRawPtr<CSSValue> outset = valueForNinePieceImageQuad(image.outset(), style);
+    CSSValue outset = valueForNinePieceImageQuad(image.outset(), style);
 
     // Create the repeat rules.
-    RefPtrWillBeRawPtr<CSSValue> repeat = valueForNinePieceImageRepeat(image);
+    CSSValue repeat = valueForNinePieceImageRepeat(image);
 
-    return createBorderImageValue(imageValue.release(), imageSlices.release(), borderSlices.release(), outset.release(), repeat.release());
+    return createBorderImageValue(imageValue, imageSlices, borderSlices, outset, repeat);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForReflection(const StyleReflection* reflection, const ComputedStyle& style)
+static CSSValue valueForReflection(const StyleReflection* reflection, const ComputedStyle& style)
 {
     if (!reflection)
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -405,9 +404,8 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valuesForGridShorthand(const StylePr
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSlashSeparated();
     for (size_t i = 0; i < shorthand.length(); ++i) {
-        RefPtrWillBeRawPtr<CSSValue> value = ComputedStyleCSSValueMapping::get(shorthand.properties()[i], style, layoutObject, styledNode, allowVisitedStyle);
-        ASSERT(value);
-        list->append(value.release());
+        NullableCSSValue value = ComputedStyleCSSValueMapping::get(shorthand.properties()[i], style, layoutObject, styledNode, allowVisitedStyle);
+        list->append(*value);
     }
     return list.release();
 }
@@ -416,9 +414,8 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valuesForShorthandProperty(const Sty
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     for (size_t i = 0; i < shorthand.length(); ++i) {
-        RefPtrWillBeRawPtr<CSSValue> value = ComputedStyleCSSValueMapping::get(shorthand.properties()[i], style, layoutObject, styledNode, allowVisitedStyle);
-        ASSERT(value);
-        list->append(value);
+        NullableCSSValue value = ComputedStyleCSSValueMapping::get(shorthand.properties()[i], style, layoutObject, styledNode, allowVisitedStyle);
+        list->append(*value);
     }
     return list.release();
 }
@@ -431,11 +428,10 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valuesForBackgroundShorthand(const C
         RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSlashSeparated();
         RefPtrWillBeRawPtr<CSSValueList> beforeSlash = CSSValueList::createSpaceSeparated();
         if (!currLayer->next()) { // color only for final layer
-            RefPtrWillBeRawPtr<CSSValue> value = ComputedStyleCSSValueMapping::get(CSSPropertyBackgroundColor, style, layoutObject, styledNode, allowVisitedStyle);
-            ASSERT(value);
-            beforeSlash->append(value);
+            NullableCSSValue value = ComputedStyleCSSValueMapping::get(CSSPropertyBackgroundColor, style, layoutObject, styledNode, allowVisitedStyle);
+            beforeSlash->append(*value);
         }
-        beforeSlash->append(currLayer->image() ? currLayer->image()->cssValue() : cssValuePool().createIdentifierValue(CSSValueNone));
+        beforeSlash->append(currLayer->image() ? *currLayer->image()->cssValue() : cssValuePool().createIdentifierValue(CSSValueNone));
         beforeSlash->append(valueForFillRepeat(currLayer->repeatX(), currLayer->repeatY()));
         beforeSlash->append(cssValuePool().createValue(currLayer->attachment()));
         beforeSlash->append(createPositionListForLayer(CSSPropertyBackgroundPosition, *currLayer, style));
@@ -542,7 +538,7 @@ static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> valueForFontWeight(const Comput
     return cssValuePool().createValue(style.fontDescription().weight());
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> specifiedValueForGridTrackBreadth(const GridLength& trackBreadth, const ComputedStyle& style)
+static CSSValue specifiedValueForGridTrackBreadth(const GridLength& trackBreadth, const ComputedStyle& style)
 {
     if (!trackBreadth.isLength())
         return cssValuePool().createValue(trackBreadth.flex(), CSSPrimitiveValue::CSS_FR);
@@ -553,7 +549,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> specifiedValueForGridTrackBreadth(const
     return zoomAdjustedPixelValueForLength(trackBreadthLength, style);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> specifiedValueForGridTrackSize(const GridTrackSize& trackSize, const ComputedStyle& style)
+static CSSValue specifiedValueForGridTrackSize(const GridTrackSize& trackSize, const ComputedStyle& style)
 {
     switch (trackSize.type()) {
     case LengthTrackSizing:
@@ -565,7 +561,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> specifiedValueForGridTrackSize(const Gri
         return minMaxTrackBreadths.release();
     }
     ASSERT_NOT_REACHED();
-    return nullptr;
+    return specifiedValueForGridTrackBreadth(trackSize.length(), style);
 }
 
 static void addValuesForNamedGridLinesAtIndex(const OrderedNamedGridLines& orderedNamedGridLines, size_t i, CSSValueList& list)
@@ -580,7 +576,7 @@ static void addValuesForNamedGridLinesAtIndex(const OrderedNamedGridLines& order
     list.append(lineNames.release());
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForGridTrackList(GridTrackSizingDirection direction, const LayoutObject* layoutObject, const ComputedStyle& style)
+static CSSValue valueForGridTrackList(GridTrackSizingDirection direction, const LayoutObject* layoutObject, const ComputedStyle& style)
 {
     const Vector<GridTrackSize>& trackSizes = direction == ForColumns ? style.gridTemplateColumns() : style.gridTemplateRows();
     const OrderedNamedGridLines& orderedNamedGridLines = direction == ForColumns ? style.orderedNamedGridColumnLines() : style.orderedNamedGridRowLines();
@@ -625,7 +621,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForGridTrackList(GridTrackSizingDir
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForGridPosition(const GridPosition& position)
+static CSSValue valueForGridPosition(const GridPosition& position)
 {
     if (position.isAuto())
         return cssValuePool().createIdentifierValue(CSSValueAuto);
@@ -655,7 +651,7 @@ static LayoutRect sizingBox(const LayoutObject* layoutObject)
     return box->style()->boxSizing() == BORDER_BOX ? box->borderBoxRect() : box->computedCSSContentBoxRect();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> scrollBlocksOnFlagsToCSSValue(WebScrollBlocksOn scrollBlocksOn)
+static CSSValue scrollBlocksOnFlagsToCSSValue(WebScrollBlocksOn scrollBlocksOn)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
 
@@ -672,7 +668,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> scrollBlocksOnFlagsToCSSValue(WebScrollB
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> renderTextDecorationFlagsToCSSValue(int textDecoration)
+static CSSValue renderTextDecorationFlagsToCSSValue(int textDecoration)
 {
     // Blink value is ignored.
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
@@ -688,7 +684,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> renderTextDecorationFlagsToCSSValue(int
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForTextDecorationStyle(TextDecorationStyle textDecorationStyle)
+static CSSValue valueForTextDecorationStyle(TextDecorationStyle textDecorationStyle)
 {
     switch (textDecorationStyle) {
     case TextDecorationStyleSolid:
@@ -707,7 +703,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForTextDecorationStyle(TextDecorati
     return cssValuePool().createExplicitInitialValue();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> touchActionFlagsToCSSValue(TouchAction touchAction)
+static CSSValue touchActionFlagsToCSSValue(TouchAction touchAction)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     if (touchAction == TouchActionAuto)
@@ -737,7 +733,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> touchActionFlagsToCSSValue(TouchAction t
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForWillChange(const Vector<CSSPropertyID>& willChangeProperties, bool willChangeContents, bool willChangeScrollPosition)
+static CSSValue valueForWillChange(const Vector<CSSPropertyID>& willChangeProperties, bool willChangeContents, bool willChangeScrollPosition)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (willChangeContents)
@@ -751,7 +747,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForWillChange(const Vector<CSSPrope
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDelay(const CSSTimingData* timingData)
+static CSSValue valueForAnimationDelay(const CSSTimingData* timingData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (timingData) {
@@ -763,7 +759,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDelay(const CSSTimingDa
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDirection(Timing::PlaybackDirection direction)
+static CSSValue valueForAnimationDirection(Timing::PlaybackDirection direction)
 {
     switch (direction) {
     case Timing::PlaybackDirectionNormal:
@@ -776,11 +772,11 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDirection(Timing::Playb
         return cssValuePool().createIdentifierValue(CSSValueAlternateReverse);
     default:
         ASSERT_NOT_REACHED();
-        return nullptr;
+        return cssValuePool().createIdentifierValue(CSSValueNormal);
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDuration(const CSSTimingData* timingData)
+static CSSValue valueForAnimationDuration(const CSSTimingData* timingData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (timingData) {
@@ -792,7 +788,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDuration(const CSSTimin
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationFillMode(Timing::FillMode fillMode)
+static CSSValue valueForAnimationFillMode(Timing::FillMode fillMode)
 {
     switch (fillMode) {
     case Timing::FillModeNone:
@@ -805,18 +801,18 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationFillMode(Timing::FillMo
         return cssValuePool().createIdentifierValue(CSSValueBoth);
     default:
         ASSERT_NOT_REACHED();
-        return nullptr;
+        return cssValuePool().createIdentifierValue(CSSValueNone);
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationIterationCount(double iterationCount)
+static CSSValue valueForAnimationIterationCount(double iterationCount)
 {
     if (iterationCount == std::numeric_limits<double>::infinity())
         return cssValuePool().createIdentifierValue(CSSValueInfinite);
     return cssValuePool().createValue(iterationCount, CSSPrimitiveValue::CSS_NUMBER);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationPlayState(EAnimPlayState playState)
+static CSSValue valueForAnimationPlayState(EAnimPlayState playState)
 {
     if (playState == AnimPlayStatePlaying)
         return cssValuePool().createIdentifierValue(CSSValueRunning);
@@ -824,7 +820,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationPlayState(EAnimPlayStat
     return cssValuePool().createIdentifierValue(CSSValuePaused);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> createTimingFunctionValue(const TimingFunction* timingFunction)
+static CSSValue createTimingFunctionValue(const TimingFunction* timingFunction)
 {
     switch (timingFunction->type()) {
     case TimingFunction::CubicBezierFunction:
@@ -847,7 +843,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> createTimingFunctionValue(const TimingFu
                     break;
                 default:
                     ASSERT_NOT_REACHED();
-                    return nullptr;
+                    valueId = CSSValueEase;
                 }
                 return cssValuePool().createIdentifierValue(valueId);
             }
@@ -872,7 +868,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> createTimingFunctionValue(const TimingFu
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationTimingFunction(const CSSTimingData* timingData)
+static CSSValue valueForAnimationTimingFunction(const CSSTimingData* timingData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (timingData) {
@@ -898,10 +894,10 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valuesForBorderRadiusCorner(LengthSi
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForBorderRadiusCorner(LengthSize radius, const ComputedStyle& style)
+static CSSValue valueForBorderRadiusCorner(LengthSize radius, const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = valuesForBorderRadiusCorner(radius, style);
-    if (list->item(0)->equals(*list->item(1)))
+    if (list->item(0).equals(list->item(1)))
         return list->item(0);
     return list.release();
 }
@@ -945,7 +941,7 @@ static PassRefPtrWillBeRawPtr<CSSFunctionValue> valueForMatrixTransform(const Tr
     return transformValue.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> computedTransform(const LayoutObject* layoutObject, const ComputedStyle& style)
+static CSSValue computedTransform(const LayoutObject* layoutObject, const ComputedStyle& style)
 {
     if (!layoutObject || !layoutObject->hasTransformRelatedProperty() || !style.hasTransform())
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -964,7 +960,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> computedTransform(const LayoutObject* la
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> createTransitionPropertyValue(const CSSTransitionData::TransitionProperty& property)
+static CSSValue createTransitionPropertyValue(const CSSTransitionData::TransitionProperty& property)
 {
     if (property.propertyType == CSSTransitionData::TransitionNone)
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -976,7 +972,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> createTransitionPropertyValue(const CSST
     return cssValuePool().createValue(getPropertyNameString(property.unresolvedProperty), CSSPrimitiveValue::CSS_CUSTOM_IDENT);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForTransitionProperty(const CSSTransitionData* transitionData)
+static CSSValue valueForTransitionProperty(const CSSTransitionData* transitionData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (transitionData) {
@@ -988,7 +984,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForTransitionProperty(const CSSTran
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> createLineBoxContainValue(unsigned lineBoxContain)
+static CSSValue createLineBoxContainValue(unsigned lineBoxContain)
 {
     if (!lineBoxContain)
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -1011,7 +1007,7 @@ CSSValueID valueForQuoteType(const QuoteType quoteType)
     return CSSValueInvalid;
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForContentData(const ComputedStyle& style)
+static CSSValue valueForContentData(const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     for (const ContentData* contentData = style.contentData(); contentData; contentData = contentData->next()) {
@@ -1028,7 +1024,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForContentData(const ComputedStyle&
         } else if (contentData->isImage()) {
             const StyleImage* image = toImageContentData(contentData)->image();
             ASSERT(image);
-            list->append(image->cssValue());
+            list->append(*image->cssValue());
         } else if (contentData->isText()) {
             list->append(cssValuePool().createValue(toTextContentData(contentData)->text(), CSSPrimitiveValue::CSS_STRING));
         } else if (contentData->isQuote()) {
@@ -1041,7 +1037,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForContentData(const ComputedStyle&
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForCounterDirectives(const ComputedStyle& style, CSSPropertyID propertyID)
+static CSSValue valueForCounterDirectives(const ComputedStyle& style, CSSPropertyID propertyID)
 {
     const CounterDirectiveMap* map = style.counterDirectives();
     if (!map)
@@ -1064,7 +1060,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForCounterDirectives(const Computed
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForShape(const ComputedStyle& style, ShapeValue* shapeValue)
+static CSSValue valueForShape(const ComputedStyle& style, ShapeValue* shapeValue)
 {
     if (!shapeValue)
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -1072,7 +1068,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForShape(const ComputedStyle& style
         return cssValuePool().createValue(shapeValue->cssBox());
     if (shapeValue->type() == ShapeValue::Image) {
         if (shapeValue->image())
-            return shapeValue->image()->cssValue();
+            return *shapeValue->image()->cssValue();
         return cssValuePool().createIdentifierValue(CSSValueNone);
     }
 
@@ -1089,26 +1085,26 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valuesForSidesShorthand(const StyleP
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     // Assume the properties are in the usual order top, right, bottom, left.
-    RefPtrWillBeRawPtr<CSSValue> topValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[0], style, layoutObject, styledNode, allowVisitedStyle);
-    RefPtrWillBeRawPtr<CSSValue> rightValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[1], style, layoutObject, styledNode, allowVisitedStyle);
-    RefPtrWillBeRawPtr<CSSValue> bottomValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[2], style, layoutObject, styledNode, allowVisitedStyle);
-    RefPtrWillBeRawPtr<CSSValue> leftValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[3], style, layoutObject, styledNode, allowVisitedStyle);
+    NullableCSSValue topValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[0], style, layoutObject, styledNode, allowVisitedStyle);
+    NullableCSSValue rightValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[1], style, layoutObject, styledNode, allowVisitedStyle);
+    NullableCSSValue bottomValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[2], style, layoutObject, styledNode, allowVisitedStyle);
+    NullableCSSValue leftValue = ComputedStyleCSSValueMapping::get(shorthand.properties()[3], style, layoutObject, styledNode, allowVisitedStyle);
 
     // All 4 properties must be specified.
     if (!topValue || !rightValue || !bottomValue || !leftValue)
         return nullptr;
 
-    bool showLeft = !compareCSSValuePtr(rightValue, leftValue);
-    bool showBottom = !compareCSSValuePtr(topValue, bottomValue) || showLeft;
-    bool showRight = !compareCSSValuePtr(topValue, rightValue) || showBottom;
+    bool showLeft = !rightValue->equals(*leftValue);
+    bool showBottom = !topValue->equals(*bottomValue) || showLeft;
+    bool showRight = !topValue->equals(*rightValue) || showBottom;
 
-    list->append(topValue.release());
+    list->append(*topValue);
     if (showRight)
-        list->append(rightValue.release());
+        list->append(*rightValue);
     if (showBottom)
-        list->append(bottomValue.release());
+        list->append(*bottomValue);
     if (showLeft)
-        list->append(leftValue.release());
+        list->append(*leftValue);
 
     return list.release();
 }
@@ -1150,7 +1146,7 @@ static PassRefPtrWillBeRawPtr<CSSValueList> valueForBorderRadiusShorthand(const
     if (showVerticalBottomLeft)
         verticalRadii->append(bottomLeftRadius->item(1));
 
-    if (!verticalRadii->equals(*toCSSValueList(list->item(0))))
+    if (!verticalRadii->equals(toCSSValueList(list->item(0))))
         list->append(verticalRadii.release());
 
     return list.release();
@@ -1172,7 +1168,7 @@ static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> glyphOrientationToCSSPrimitiveV
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> strokeDashArrayToCSSValueList(const SVGDashArray& dashes, const ComputedStyle& style)
+static CSSValue strokeDashArrayToCSSValueList(const SVGDashArray& dashes, const ComputedStyle& style)
 {
     if (dashes.isEmpty())
         return CSSPrimitiveValue::createIdentifier(CSSValueNone);
@@ -1184,7 +1180,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> strokeDashArrayToCSSValueList(const SVGD
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> paintOrderToCSSValueList(EPaintOrder paintorder)
+static CSSValue paintOrderToCSSValueList(EPaintOrder paintorder)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     do {
@@ -1205,7 +1201,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> paintOrderToCSSValueList(EPaintOrder pai
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> adjustSVGPaintForCurrentColor(SVGPaintType paintType, const String& url, const Color& color, const Color& currentColor)
+static CSSValue adjustSVGPaintForCurrentColor(SVGPaintType paintType, const String& url, const Color& color, const Color& currentColor)
 {
     if (paintType >= SVG_PAINTTYPE_URI_NONE) {
         RefPtrWillBeRawPtr<CSSValueList> values = CSSValueList::createSpaceSeparated();
@@ -1231,7 +1227,7 @@ static inline String serializeAsFragmentIdentifier(const AtomicString& resource)
     return "#" + resource;
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForShadowData(const ShadowData& shadow, const ComputedStyle& style, bool useSpread)
+CSSValue ComputedStyleCSSValueMapping::valueForShadowData(const ShadowData& shadow, const ComputedStyle& style, bool useSpread)
 {
     RefPtrWillBeRawPtr<CSSPrimitiveValue> x = zoomAdjustedPixelValue(shadow.x(), style);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> y = zoomAdjustedPixelValue(shadow.y(), style);
@@ -1242,7 +1238,7 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForShadowDat
     return CSSShadowValue::create(x.release(), y.release(), blur.release(), spread.release(), shadowStyle.release(), color.release());
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForShadowList(const ShadowList* shadowList, const ComputedStyle& style, bool useSpread)
+CSSValue ComputedStyleCSSValueMapping::valueForShadowList(const ShadowList* shadowList, const ComputedStyle& style, bool useSpread)
 {
     if (!shadowList)
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -1254,7 +1250,7 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForShadowLis
     return list.release();
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForFilter(const ComputedStyle& style)
+CSSValue ComputedStyleCSSValueMapping::valueForFilter(const ComputedStyle& style)
 {
     if (style.filter().operations().isEmpty())
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -1324,7 +1320,7 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForFilter(co
     return list.release();
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForFont(const ComputedStyle& style)
+CSSValue ComputedStyleCSSValueMapping::valueForFont(const ComputedStyle& style)
 {
     // Add a slash between size and line-height.
     RefPtrWillBeRawPtr<CSSValueList> sizeAndLineHeight = CSSValueList::createSlashSeparated();
@@ -1342,7 +1338,7 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::valueForFont(cons
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapDestination(const LengthPoint& destination, const ComputedStyle& style)
+static CSSValue valueForScrollSnapDestination(const LengthPoint& destination, const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(zoomAdjustedPixelValueForLength(destination.x(), style));
@@ -1350,7 +1346,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapDestination(const Leng
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapPoints(const ScrollSnapPoints& points, const ComputedStyle& style)
+static CSSValue valueForScrollSnapPoints(const ScrollSnapPoints& points, const ComputedStyle& style)
 {
     if (points.hasRepeat) {
         RefPtrWillBeRawPtr<CSSFunctionValue> repeat = CSSFunctionValue::create(CSSValueRepeat);
@@ -1361,7 +1357,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapPoints(const ScrollSna
     return cssValuePool().createIdentifierValue(CSSValueNone);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapCoordinate(const Vector<LengthPoint>& coordinates, const ComputedStyle& style)
+static CSSValue valueForScrollSnapCoordinate(const Vector<LengthPoint>& coordinates, const ComputedStyle& style)
 {
     if (coordinates.isEmpty())
         return cssValuePool().createIdentifierValue(CSSValueNone);
@@ -1378,7 +1374,7 @@ static PassRefPtrWillBeRawPtr<CSSValue> valueForScrollSnapCoordinate(const Vecto
     return list.release();
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::get(CSSPropertyID propertyID, const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
+NullableCSSValue ComputedStyleCSSValueMapping::get(CSSPropertyID propertyID, const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
 {
     const SVGComputedStyle& svgStyle = style.svgStyle();
     propertyID = CSSProperty::resolveDirectionAwareProperty(propertyID, style.direction(), style.writingMode());
@@ -1394,7 +1390,7 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::get(CSSPropertyID
         const FillLayer* currLayer = propertyID == CSSPropertyWebkitMaskImage ? &style.maskLayers() : &style.backgroundLayers();
         for (; currLayer; currLayer = currLayer->next()) {
             if (currLayer->image())
-                list->append(currLayer->image()->cssValue());
+                list->append(*currLayer->image()->cssValue());
             else
                 list->append(cssValuePool().createIdentifierValue(CSSValueNone));
         }
@@ -1590,15 +1586,15 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::get(CSSPropertyID
             list = CSSValueList::createCommaSeparated();
             for (unsigned i = 0; i < cursors->size(); ++i) {
                 if (StyleImage* image = cursors->at(i).image())
-                    list->append(image->cssValue());
+                    list->append(*image->cssValue());
             }
         }
-        RefPtrWillBeRawPtr<CSSValue> value = cssValuePool().createValue(style.cursor());
+        CSSValue value = cssValuePool().createValue(style.cursor());
         if (list) {
-            list->append(value.release());
+            list->append(value);
             return list.release();
         }
-        return value.release();
+        return value;
     }
     case CSSPropertyDirection:
         return cssValuePool().createValue(style.direction());
@@ -2363,17 +2359,17 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::get(CSSPropertyID
     case CSSPropertyBackground:
         return valuesForBackgroundShorthand(style, layoutObject, styledNode, allowVisitedStyle);
     case CSSPropertyBorder: {
-        RefPtrWillBeRawPtr<CSSValue> value = get(CSSPropertyBorderTop, style, layoutObject, styledNode, allowVisitedStyle);
+        NullableCSSValue value = get(CSSPropertyBorderTop, style, layoutObject, styledNode, allowVisitedStyle);
         const CSSPropertyID properties[] = {
             CSSPropertyBorderRight,
             CSSPropertyBorderBottom,
             CSSPropertyBorderLeft
         };
         for (size_t i = 0; i < WTF_ARRAY_LENGTH(properties); ++i) {
-            if (!compareCSSValuePtr<CSSValue>(value, get(properties[i], style, layoutObject, styledNode, allowVisitedStyle)))
+            if (value != get(properties[i], style, layoutObject, styledNode, allowVisitedStyle))
                 return nullptr;
         }
-        return value.release();
+        return *value;
     }
     case CSSPropertyBorderBottom:
         return valuesForShorthandProperty(borderBottomShorthand(), style, layoutObject, styledNode, allowVisitedStyle);