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

Source/core/css/ComputedStyleCSSValueMapping.cpp

 /*
  * Copyright (C) 2004 Zack Rusin <zack@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2011 Sencha, Inc. All rights reserved.
  * Copyright (C) 2015 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ skipping 91 matching lines @@
     positionList->append(zoomAdjustedPixelValueForLength(layer.yPosition(), style));
     return positionList.release();
 }
 
 PassRefPtrWillBeRawPtr<CSSPrimitiveValue> ComputedStyleCSSValueMapping::currentColorOrValidColor(const ComputedStyle& style, const StyleColor& color)
 {
     // This function does NOT look at visited information, so that computed style doesn't expose that.
     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);
 
     if (fillSize.type == Cover)
         return cssValuePool().createIdentifierValue(CSSValueCover);
 
     if (fillSize.size.height().isAuto())
         return zoomAdjustedPixelValueForLength(fillSize.size.width(), style);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(zoomAdjustedPixelValueForLength(fillSize.size.width(), style));
     list->append(zoomAdjustedPixelValueForLength(fillSize.size.height(), style));
     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.
     if (xRepeat == yRepeat)
         return cssValuePool().createValue(xRepeat);
     if (xRepeat == RepeatFill && yRepeat == NoRepeatFill)
         return cssValuePool().createIdentifierValue(CSSValueRepeatX);
     if (xRepeat == NoRepeatFill && yRepeat == RepeatFill)
         return cssValuePool().createIdentifierValue(CSSValueRepeatY);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(cssValuePool().createValue(xRepeat));
     list->append(cssValuePool().createValue(yRepeat));
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForFillSourceType(EMaskSourceType type)
+static CSSValue valueForFillSourceType(EMaskSourceType type)
 {
     switch (type) {
     case MaskAlpha:
         return cssValuePool().createValue(CSSValueAlpha);
     case MaskLuminance:
         return cssValuePool().createValue(CSSValueLuminance);
     }
 
     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) {
     case CSSPropertyLeft:
         offset = style.left();
         break;
     case CSSPropertyRight:
         offset = style.right();
         break;
     case CSSPropertyTop:
         offset = style.top();
         break;
     case CSSPropertyBottom:
         offset = style.bottom();
         break;
     default:
-        return nullptr;
+        return cssValuePool().createIdentifierValue(CSSValueAuto);
     }
 
     if (offset.hasPercent() && layoutObject && layoutObject->isBox() && layoutObject->isPositioned()) {
         LayoutUnit containingBlockSize = (propertyID == CSSPropertyLeft || propertyID == CSSPropertyRight) ?
             toLayoutBox(layoutObject)->containingBlockLogicalWidthForContent() :
             toLayoutBox(layoutObject)->containingBlockLogicalHeightForGetComputedStyle();
         return zoomAdjustedPixelValue(valueForLength(offset, containingBlockSize), style);
     }
     if (offset.isAuto()) {
         // FIXME: It's not enough to simply return "auto" values for one offset if the other side is defined.
@@ skipping 118 matching lines @@
         return CSSValueRepeat;
     case RoundImageRule:
         return CSSValueRound;
     case SpaceImageRule:
         return CSSValueSpace;
     default:
         return CSSValueStretch;
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForNinePieceImageRepeat(const NinePieceImage& image)
+static CSSValue valueForNinePieceImageRepeat(const NinePieceImage& image)
 {
     RefPtrWillBeRawPtr<CSSPrimitiveValue> horizontalRepeat = nullptr;
     RefPtrWillBeRawPtr<CSSPrimitiveValue> verticalRepeat = nullptr;
 
     horizontalRepeat = cssValuePool().createIdentifierValue(valueForRepeatRule(image.horizontalRule()));
     if (image.horizontalRule() == image.verticalRule())
         verticalRepeat = horizontalRepeat;
     else
         verticalRepeat = cssValuePool().createIdentifierValue(valueForRepeatRule(image.verticalRule()));
     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();
 
     // Create the image slice.
     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);
 
     RefPtrWillBeRawPtr<CSSPrimitiveValue> offset = nullptr;
     // TODO(alancutter): Make this work correctly for calc lengths.
     if (reflection->offset().hasPercent())
         offset = cssValuePool().createValue(reflection->offset().percent(), CSSPrimitiveValue::CSS_PERCENTAGE);
     else
         offset = zoomAdjustedPixelValue(reflection->offset().value(), style);
@@ skipping 34 matching lines @@
     if (itemPosition >= ItemPositionCenter && overflowAlignment != OverflowAlignmentDefault)
         result->append(CSSPrimitiveValue::create(overflowAlignment));
     ASSERT(result->length() <= 2);
     return result.release();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valuesForGridShorthand(const StylePropertyShorthand& shorthand, const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
 {
     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();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valuesForShorthandProperty(const StylePropertyShorthand& shorthand, const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
 {
     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();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valuesForBackgroundShorthand(const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
 {
     RefPtrWillBeRawPtr<CSSValueList> ret = CSSValueList::createCommaSeparated();
     const FillLayer* currLayer = &style.backgroundLayers();
     for (; currLayer; currLayer = currLayer->next()) {
         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));
         list->append(beforeSlash);
         RefPtrWillBeRawPtr<CSSValueList> afterSlash = CSSValueList::createSpaceSeparated();
         afterSlash->append(valueForFillSize(currLayer->size(), style));
         afterSlash->append(cssValuePool().createValue(currLayer->origin()));
         afterSlash->append(cssValuePool().createValue(currLayer->clip()));
         list->append(afterSlash);
         ret->append(list);
@@ skipping 86 matching lines @@
 static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> valueForFontVariant(const ComputedStyle& style)
 {
     return cssValuePool().createValue(style.fontDescription().variant());
 }
 
 static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> valueForFontWeight(const ComputedStyle& style)
 {
     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);
 
     const Length& trackBreadthLength = trackBreadth.length();
     if (trackBreadthLength.isAuto())
         return cssValuePool().createIdentifierValue(CSSValueAuto);
     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:
         return specifiedValueForGridTrackBreadth(trackSize.length(), style);
     case MinMaxTrackSizing:
         RefPtrWillBeRawPtr<CSSFunctionValue> minMaxTrackBreadths = CSSFunctionValue::create(CSSValueMinmax);
         minMaxTrackBreadths->append(specifiedValueForGridTrackBreadth(trackSize.minTrackBreadth(), style));
         minMaxTrackBreadths->append(specifiedValueForGridTrackBreadth(trackSize.maxTrackBreadth(), style));
         return minMaxTrackBreadths.release();
     }
     ASSERT_NOT_REACHED();
-    return nullptr;
+    return specifiedValueForGridTrackBreadth(trackSize.length(), style);
 }
 
 static void addValuesForNamedGridLinesAtIndex(const OrderedNamedGridLines& orderedNamedGridLines, size_t i, CSSValueList& list)
 {
     const Vector<String>& namedGridLines = orderedNamedGridLines.get(i);
     if (namedGridLines.isEmpty())
         return;
 
     RefPtrWillBeRawPtr<CSSGridLineNamesValue> lineNames = CSSGridLineNamesValue::create();
     for (size_t j = 0; j < namedGridLines.size(); ++j)
         lineNames->append(cssValuePool().createValue(namedGridLines[j], CSSPrimitiveValue::CSS_CUSTOM_IDENT));
     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();
     bool isLayoutGrid = layoutObject && layoutObject->isLayoutGrid();
 
     // Handle the 'none' case.
     bool trackListIsEmpty = trackSizes.isEmpty();
     if (isLayoutGrid && trackListIsEmpty) {
         // For grids we should consider every listed track, whether implicitly or explicitly created. If we don't have
         // any explicit track and there are no children then there are no implicit tracks. We cannot simply check the
@@ skipping 24 matching lines @@
             addValuesForNamedGridLinesAtIndex(orderedNamedGridLines, i, *list);
             list->append(specifiedValueForGridTrackSize(trackSizes[i], style));
         }
         insertionIndex = trackSizes.size();
     }
     // Those are the trailing <string>* allowed in the syntax.
     addValuesForNamedGridLinesAtIndex(orderedNamedGridLines, insertionIndex, *list);
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForGridPosition(const GridPosition& position)
+static CSSValue valueForGridPosition(const GridPosition& position)
 {
     if (position.isAuto())
         return cssValuePool().createIdentifierValue(CSSValueAuto);
 
     if (position.isNamedGridArea())
         return cssValuePool().createValue(position.namedGridLine(), CSSPrimitiveValue::CSS_CUSTOM_IDENT);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     if (position.isSpan()) {
         list->append(cssValuePool().createIdentifierValue(CSSValueSpan));
         list->append(cssValuePool().createValue(position.spanPosition(), CSSPrimitiveValue::CSS_NUMBER));
     } else {
         list->append(cssValuePool().createValue(position.integerPosition(), CSSPrimitiveValue::CSS_NUMBER));
     }
 
     if (!position.namedGridLine().isNull())
         list->append(cssValuePool().createValue(position.namedGridLine(), CSSPrimitiveValue::CSS_CUSTOM_IDENT));
     return list;
 }
 
 static LayoutRect sizingBox(const LayoutObject* layoutObject)
 {
     if (!layoutObject->isBox())
         return LayoutRect();
 
     const LayoutBox* box = toLayoutBox(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();
 
     if (scrollBlocksOn == WebScrollBlocksOnNone)
         return cssValuePool().createIdentifierValue(CSSValueNone);
 
     if (scrollBlocksOn & WebScrollBlocksOnStartTouch)
         list->append(cssValuePool().createIdentifierValue(CSSValueStartTouch));
     if (scrollBlocksOn & WebScrollBlocksOnWheelEvent)
         list->append(cssValuePool().createIdentifierValue(CSSValueWheelEvent));
     if (scrollBlocksOn & WebScrollBlocksOnScrollEvent)
         list->append(cssValuePool().createIdentifierValue(CSSValueScrollEvent));
     ASSERT(list->length());
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> renderTextDecorationFlagsToCSSValue(int textDecoration)
+static CSSValue renderTextDecorationFlagsToCSSValue(int textDecoration)
 {
     // Blink value is ignored.
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     if (textDecoration & TextDecorationUnderline)
         list->append(cssValuePool().createIdentifierValue(CSSValueUnderline));
     if (textDecoration & TextDecorationOverline)
         list->append(cssValuePool().createIdentifierValue(CSSValueOverline));
     if (textDecoration & TextDecorationLineThrough)
         list->append(cssValuePool().createIdentifierValue(CSSValueLineThrough));
 
     if (!list->length())
         return cssValuePool().createIdentifierValue(CSSValueNone);
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForTextDecorationStyle(TextDecorationStyle textDecorationStyle)
+static CSSValue valueForTextDecorationStyle(TextDecorationStyle textDecorationStyle)
 {
     switch (textDecorationStyle) {
     case TextDecorationStyleSolid:
         return cssValuePool().createIdentifierValue(CSSValueSolid);
     case TextDecorationStyleDouble:
         return cssValuePool().createIdentifierValue(CSSValueDouble);
     case TextDecorationStyleDotted:
         return cssValuePool().createIdentifierValue(CSSValueDotted);
     case TextDecorationStyleDashed:
         return cssValuePool().createIdentifierValue(CSSValueDashed);
     case TextDecorationStyleWavy:
         return cssValuePool().createIdentifierValue(CSSValueWavy);
     }
 
     ASSERT_NOT_REACHED();
     return cssValuePool().createExplicitInitialValue();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> touchActionFlagsToCSSValue(TouchAction touchAction)
+static CSSValue touchActionFlagsToCSSValue(TouchAction touchAction)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     if (touchAction == TouchActionAuto)
         list->append(cssValuePool().createIdentifierValue(CSSValueAuto));
     if (touchAction & TouchActionNone) {
         ASSERT(touchAction == TouchActionNone);
         list->append(cssValuePool().createIdentifierValue(CSSValueNone));
     }
     if (touchAction == (TouchActionPanX | TouchActionPanY | TouchActionPinchZoom)) {
         list->append(cssValuePool().createIdentifierValue(CSSValueManipulation));
     } else {
         if ((touchAction & TouchActionPanX) == TouchActionPanX)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanX));
         else if (touchAction & TouchActionPanLeft)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanLeft));
         else if (touchAction & TouchActionPanRight)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanRight));
 
         if ((touchAction & TouchActionPanY) == TouchActionPanY)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanY));
         else if (touchAction & TouchActionPanUp)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanUp));
         else if (touchAction & TouchActionPanDown)
             list->append(cssValuePool().createIdentifierValue(CSSValuePanDown));
     }
     ASSERT(list->length());
     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)
         list->append(cssValuePool().createIdentifierValue(CSSValueContents));
     if (willChangeScrollPosition)
         list->append(cssValuePool().createIdentifierValue(CSSValueScrollPosition));
     for (size_t i = 0; i < willChangeProperties.size(); ++i)
         list->append(cssValuePool().createIdentifierValue(willChangeProperties[i]));
     if (!list->length())
         list->append(cssValuePool().createIdentifierValue(CSSValueAuto));
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDelay(const CSSTimingData* timingData)
+static CSSValue valueForAnimationDelay(const CSSTimingData* timingData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (timingData) {
         for (size_t i = 0; i < timingData->delayList().size(); ++i)
             list->append(cssValuePool().createValue(timingData->delayList()[i], CSSPrimitiveValue::CSS_S));
     } else {
         list->append(cssValuePool().createValue(CSSTimingData::initialDelay(), CSSPrimitiveValue::CSS_S));
     }
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationDirection(Timing::PlaybackDirection direction)
+static CSSValue valueForAnimationDirection(Timing::PlaybackDirection direction)
 {
     switch (direction) {
     case Timing::PlaybackDirectionNormal:
         return cssValuePool().createIdentifierValue(CSSValueNormal);
     case Timing::PlaybackDirectionAlternate:
         return cssValuePool().createIdentifierValue(CSSValueAlternate);
     case Timing::PlaybackDirectionReverse:
         return cssValuePool().createIdentifierValue(CSSValueReverse);
     case Timing::PlaybackDirectionAlternateReverse:
         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) {
         for (size_t i = 0; i < timingData->durationList().size(); ++i)
             list->append(cssValuePool().createValue(timingData->durationList()[i], CSSPrimitiveValue::CSS_S));
     } else {
         list->append(cssValuePool().createValue(CSSTimingData::initialDuration(), CSSPrimitiveValue::CSS_S));
     }
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationFillMode(Timing::FillMode fillMode)
+static CSSValue valueForAnimationFillMode(Timing::FillMode fillMode)
 {
     switch (fillMode) {
     case Timing::FillModeNone:
         return cssValuePool().createIdentifierValue(CSSValueNone);
     case Timing::FillModeForwards:
         return cssValuePool().createIdentifierValue(CSSValueForwards);
     case Timing::FillModeBackwards:
         return cssValuePool().createIdentifierValue(CSSValueBackwards);
     case Timing::FillModeBoth:
         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);
     ASSERT(playState == AnimPlayStatePaused);
     return cssValuePool().createIdentifierValue(CSSValuePaused);
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> createTimingFunctionValue(const TimingFunction* timingFunction)
+static CSSValue createTimingFunctionValue(const TimingFunction* timingFunction)
 {
     switch (timingFunction->type()) {
     case TimingFunction::CubicBezierFunction:
         {
             const CubicBezierTimingFunction* bezierTimingFunction = toCubicBezierTimingFunction(timingFunction);
             if (bezierTimingFunction->subType() != CubicBezierTimingFunction::Custom) {
                 CSSValueID valueId = CSSValueInvalid;
                 switch (bezierTimingFunction->subType()) {
                 case CubicBezierTimingFunction::Ease:
                     valueId = CSSValueEase;
                     break;
                 case CubicBezierTimingFunction::EaseIn:
                     valueId = CSSValueEaseIn;
                     break;
                 case CubicBezierTimingFunction::EaseOut:
                     valueId = CSSValueEaseOut;
                     break;
                 case CubicBezierTimingFunction::EaseInOut:
                     valueId = CSSValueEaseInOut;
                     break;
                 default:
                     ASSERT_NOT_REACHED();
-                    return nullptr;
+                    valueId = CSSValueEase;
                 }
                 return cssValuePool().createIdentifierValue(valueId);
             }
             return CSSCubicBezierTimingFunctionValue::create(bezierTimingFunction->x1(), bezierTimingFunction->y1(), bezierTimingFunction->x2(), bezierTimingFunction->y2());
         }
 
     case TimingFunction::StepsFunction:
         {
             const StepsTimingFunction* stepsTimingFunction = toStepsTimingFunction(timingFunction);
             StepsTimingFunction::StepAtPosition position = stepsTimingFunction->stepAtPosition();
             int steps = stepsTimingFunction->numberOfSteps();
             ASSERT(position == StepsTimingFunction::Start || position == StepsTimingFunction::End);
 
             if (steps > 1)
                 return CSSStepsTimingFunctionValue::create(steps, position);
             CSSValueID valueId = position == StepsTimingFunction::Start ? CSSValueStepStart : CSSValueStepEnd;
             return cssValuePool().createIdentifierValue(valueId);
         }
 
     default:
         return cssValuePool().createIdentifierValue(CSSValueLinear);
     }
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> valueForAnimationTimingFunction(const CSSTimingData* timingData)
+static CSSValue valueForAnimationTimingFunction(const CSSTimingData* timingData)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     if (timingData) {
         for (size_t i = 0; i < timingData->timingFunctionList().size(); ++i)
             list->append(createTimingFunctionValue(timingData->timingFunctionList()[i].get()));
     } else {
         list->append(createTimingFunctionValue(CSSTimingData::initialTimingFunction().get()));
     }
     return list.release();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valuesForBorderRadiusCorner(LengthSize radius, const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     if (radius.width().type() == Percent)
         list->append(cssValuePool().createValue(radius.width().percent(), CSSPrimitiveValue::CSS_PERCENTAGE));
     else
         list->append(zoomAdjustedPixelValueForLength(radius.width(), style));
     if (radius.height().type() == Percent)
         list->append(cssValuePool().createValue(radius.height().percent(), CSSPrimitiveValue::CSS_PERCENTAGE));
     else
         list->append(zoomAdjustedPixelValueForLength(radius.height(), style));
     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();
 }
 
 static PassRefPtrWillBeRawPtr<CSSFunctionValue> valueForMatrixTransform(const TransformationMatrix& transform, const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSFunctionValue> transformValue = nullptr;
     if (transform.isAffine()) {
         transformValue = CSSFunctionValue::create(CSSValueMatrix);
 
@@ skipping 23 matching lines @@
 
         transformValue->append(zoomAdjustedNumberValue(transform.m41(), style));
         transformValue->append(zoomAdjustedNumberValue(transform.m42(), style));
         transformValue->append(zoomAdjustedNumberValue(transform.m43(), style));
         transformValue->append(cssValuePool().createValue(transform.m44(), CSSPrimitiveValue::CSS_NUMBER));
     }
 
     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);
 
     IntRect box;
     if (layoutObject->isBox())
         box = pixelSnappedIntRect(toLayoutBox(layoutObject)->borderBoxRect());
 
     TransformationMatrix transform;
     style.applyTransform(transform, LayoutSize(box.size()), ComputedStyle::ExcludeTransformOrigin, ComputedStyle::ExcludeMotionPath, ComputedStyle::ExcludeIndependentTransformProperties);
 
     // FIXME: Need to print out individual functions (https://bugs.webkit.org/show_bug.cgi?id=23924)
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(valueForMatrixTransform(transform, style));
 
     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);
     if (property.propertyType == CSSTransitionData::TransitionAll)
         return cssValuePool().createIdentifierValue(CSSValueAll);
     if (property.propertyType == CSSTransitionData::TransitionUnknown)
         return cssValuePool().createValue(property.propertyString, CSSPrimitiveValue::CSS_CUSTOM_IDENT);
     ASSERT(property.propertyType == CSSTransitionData::TransitionSingleProperty);
     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) {
         for (size_t i = 0; i < transitionData->propertyList().size(); ++i)
             list->append(createTransitionPropertyValue(transitionData->propertyList()[i]));
     } else {
         list->append(cssValuePool().createIdentifierValue(CSSValueAll));
     }
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> createLineBoxContainValue(unsigned lineBoxContain)
+static CSSValue createLineBoxContainValue(unsigned lineBoxContain)
 {
     if (!lineBoxContain)
         return cssValuePool().createIdentifierValue(CSSValueNone);
     return CSSLineBoxContainValue::create(lineBoxContain);
 }
 
 CSSValueID valueForQuoteType(const QuoteType quoteType)
 {
     switch (quoteType) {
     case NO_OPEN_QUOTE:
         return CSSValueNoOpenQuote;
     case NO_CLOSE_QUOTE:
         return CSSValueNoCloseQuote;
     case CLOSE_QUOTE:
         return CSSValueCloseQuote;
     case OPEN_QUOTE:
         return CSSValueOpenQuote;
     }
     ASSERT_NOT_REACHED();
     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()) {
         if (contentData->isCounter()) {
             const CounterContent* counter = toCounterContentData(contentData)->counter();
             ASSERT(counter);
             RefPtrWillBeRawPtr<CSSPrimitiveValue> identifier = cssValuePool().createValue(counter->identifier(), CSSPrimitiveValue::CSS_CUSTOM_IDENT);
             RefPtrWillBeRawPtr<CSSPrimitiveValue> separator = cssValuePool().createValue(counter->separator(), CSSPrimitiveValue::CSS_CUSTOM_IDENT);
             CSSValueID listStyleIdent = CSSValueNone;
             if (counter->listStyle() != NoneListStyle)
                 listStyleIdent = static_cast<CSSValueID>(CSSValueDisc + counter->listStyle());
             RefPtrWillBeRawPtr<CSSPrimitiveValue> listStyle = cssValuePool().createIdentifierValue(listStyleIdent);
             list->append(cssValuePool().createValue(Counter::create(identifier.release(), listStyle.release(), separator.release())));
         } 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()) {
             const QuoteType quoteType = toQuoteContentData(contentData)->quote();
             list->append(cssValuePool().createIdentifierValue(valueForQuoteType(quoteType)));
         } else {
             ASSERT_NOT_REACHED();
         }
     }
     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)
         return cssValuePool().createIdentifierValue(CSSValueNone);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     for (const auto& item : *map) {
         bool isValidCounterValue = propertyID == CSSPropertyCounterIncrement ? item.value.isIncrement() : item.value.isReset();
         if (!isValidCounterValue)
             continue;
 
         list->append(cssValuePool().createValue(item.key, CSSPrimitiveValue::CSS_CUSTOM_IDENT));
         short number = propertyID == CSSPropertyCounterIncrement ? item.value.incrementValue() : item.value.resetValue();
         list->append(cssValuePool().createValue((double)number, CSSPrimitiveValue::CSS_NUMBER));
     }
 
     if (!list->length())
         return cssValuePool().createIdentifierValue(CSSValueNone);
 
     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);
     if (shapeValue->type() == ShapeValue::Box)
         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);
     }
 
     ASSERT(shapeValue->type() == ShapeValue::Shape);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(valueForBasicShape(style, shapeValue->shape()));
     if (shapeValue->cssBox() != BoxMissing)
         list->append(cssValuePool().createValue(shapeValue->cssBox()));
     return list.release();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valuesForSidesShorthand(const StylePropertyShorthand& shorthand, const ComputedStyle& style, const LayoutObject* layoutObject, Node* styledNode, bool allowVisitedStyle)
 {
     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 != leftValue;
+    bool showBottom = (topValue != bottomValue) || showLeft;
+    bool showRight = (topValue != 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();
 }
 
 static PassRefPtrWillBeRawPtr<CSSValueList> valueForBorderRadiusShorthand(const ComputedStyle& style)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSlashSeparated();
 
     bool showHorizontalBottomLeft = style.borderTopRightRadius().width() != style.borderBottomLeftRadius().width();
     bool showHorizontalBottomRight = showHorizontalBottomLeft || (style.borderBottomRightRadius().width() != style.borderTopLeftRadius().width());
@@ skipping 21 matching lines @@
 
     RefPtrWillBeRawPtr<CSSValueList> verticalRadii = CSSValueList::createSpaceSeparated();
     verticalRadii->append(topLeftRadius->item(1));
     if (showVerticalTopRight)
         verticalRadii->append(topRightRadius->item(1));
     if (showVerticalBottomRight)
         verticalRadii->append(bottomRightRadius->item(1));
     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();
 }
 
 static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> glyphOrientationToCSSPrimitiveValue(EGlyphOrientation orientation)
 {
     switch (orientation) {
     case GO_0DEG:
         return CSSPrimitiveValue::create(0.0f, CSSPrimitiveValue::CSS_DEG);
     case GO_90DEG:
         return CSSPrimitiveValue::create(90.0f, CSSPrimitiveValue::CSS_DEG);
     case GO_180DEG:
         return CSSPrimitiveValue::create(180.0f, CSSPrimitiveValue::CSS_DEG);
     case GO_270DEG:
         return CSSPrimitiveValue::create(270.0f, CSSPrimitiveValue::CSS_DEG);
     default:
         return nullptr;
     }
 }
 
-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);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     for (const Length& dashLength : dashes.vector())
         list->append(zoomAdjustedPixelValueForLength(dashLength, style));
 
     return list.release();
 }
 
-static PassRefPtrWillBeRawPtr<CSSValue> paintOrderToCSSValueList(EPaintOrder paintorder)
+static CSSValue paintOrderToCSSValueList(EPaintOrder paintorder)
 {
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     do {
         EPaintOrderType paintOrderType = (EPaintOrderType)(paintorder & ((1 << kPaintOrderBitwidth) - 1));
         switch (paintOrderType) {
         case PT_FILL:
         case PT_STROKE:
         case PT_MARKERS:
             list->append(CSSPrimitiveValue::create(paintOrderType));
             break;
         case PT_NONE:
         default:
             ASSERT_NOT_REACHED();
             break;
         }
     } while (paintorder >>= kPaintOrderBitwidth);
 
     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();
         values->append(CSSPrimitiveValue::create(url, CSSPrimitiveValue::CSS_URI));
         if (paintType == SVG_PAINTTYPE_URI_NONE)
             values->append(CSSPrimitiveValue::create(CSSValueNone));
         else if (paintType == SVG_PAINTTYPE_URI_CURRENTCOLOR)
             values->append(CSSPrimitiveValue::createColor(currentColor.rgb()));
         else if (paintType == SVG_PAINTTYPE_URI_RGBCOLOR)
             values->append(CSSPrimitiveValue::createColor(color.rgb()));
         return values.release();
     }
     if (paintType == SVG_PAINTTYPE_NONE)
         return CSSPrimitiveValue::create(CSSValueNone);
     if (paintType == SVG_PAINTTYPE_CURRENTCOLOR)
         return CSSPrimitiveValue::createColor(currentColor.rgb());
 
     return CSSPrimitiveValue::createColor(color.rgb());
 }
 
 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);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> blur = zoomAdjustedPixelValue(shadow.blur(), style);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> spread = useSpread ? zoomAdjustedPixelValue(shadow.spread(), style) : PassRefPtrWillBeRawPtr<CSSPrimitiveValue>(nullptr);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> shadowStyle = shadow.style() == Normal ? PassRefPtrWillBeRawPtr<CSSPrimitiveValue>(nullptr) : cssValuePool().createIdentifierValue(CSSValueInset);
     RefPtrWillBeRawPtr<CSSPrimitiveValue> color = currentColorOrValidColor(style, shadow.color());
     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);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
     size_t shadowCount = shadowList->shadows().size();
     for (size_t i = 0; i < shadowCount; ++i)
         list->append(valueForShadowData(shadowList->shadows()[i], style, useSpread));
     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);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
 
     RefPtrWillBeRawPtr<CSSFunctionValue> filterValue = nullptr;
 
     for (const auto& operation : style.filter().operations()) {
         FilterOperation* filterOperation = operation.get();
@@ skipping 49 matching lines @@
         default:
             ASSERT_NOT_REACHED();
             break;
         }
         list->append(filterValue.release());
     }
 
     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();
     sizeAndLineHeight->append(valueForFontSize(style));
     sizeAndLineHeight->append(valueForLineHeight(style));
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
     list->append(valueForFontStyle(style));
     list->append(valueForFontVariant(style));
     list->append(valueForFontWeight(style));
     list->append(valueForFontStretch(style));
     list->append(sizeAndLineHeight.release());
     list->append(valueForFontFamily(style));
 
     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));
     list->append(zoomAdjustedPixelValueForLength(destination.y(), style));
     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);
         repeat->append(zoomAdjustedPixelValueForLength(points.repeatOffset, style));
         return repeat.release();
     }
 
     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);
 
     RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
 
     for (auto& coordinate : coordinates) {
         auto pair = CSSValueList::createSpaceSeparated();
         pair->append(zoomAdjustedPixelValueForLength(coordinate.x(), style));
         pair->append(zoomAdjustedPixelValueForLength(coordinate.y(), style));
         list->append(pair);
     }
 
     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());
     switch (propertyID) {
     case CSSPropertyInvalid:
         return nullptr;
 
     case CSSPropertyBackgroundColor:
         return allowVisitedStyle ? cssValuePool().createColorValue(style.visitedDependentColor(CSSPropertyBackgroundColor).rgb()) : currentColorOrValidColor(style, style.backgroundColor());
     case CSSPropertyBackgroundImage:
     case CSSPropertyWebkitMaskImage: {
         RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
         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));
         }
         return list.release();
     }
     case CSSPropertyBackgroundSize:
     case CSSPropertyWebkitMaskSize: {
         RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
         const FillLayer* currLayer = propertyID == CSSPropertyWebkitMaskSize ? &style.maskLayers() : &style.backgroundLayers();
         for (; currLayer; currLayer = currLayer->next())
@@ skipping 175 matching lines @@
     case CSSPropertyTabSize:
         return cssValuePool().createValue(
             style.tabSize().getPixelSize(1.0), style.tabSize().isSpaces() ? CSSPrimitiveValue::CSS_NUMBER : CSSPrimitiveValue::CSS_PX);
     case CSSPropertyCursor: {
         RefPtrWillBeRawPtr<CSSValueList> list = nullptr;
         CursorList* cursors = style.cursors();
         if (cursors && cursors->size() > 0) {
             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());
     case CSSPropertyDisplay:
         return cssValuePool().createValue(style.display());
     case CSSPropertyEmptyCells:
         return cssValuePool().createValue(style.emptyCells());
     case CSSPropertyAlignContent:
         return valueForContentPositionAndDistributionWithOverflowAlignment(resolveContentAlignmentAuto(style.alignContentPosition(), style.alignContentDistribution(), styledNode), style.alignContentOverflowAlignment(), style.alignContentDistribution());
     case CSSPropertyAlignItems:
@@ skipping 758 matching lines @@
 
     case CSSPropertyBackgroundBlendMode: {
         RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
         for (const FillLayer* currLayer = &style.backgroundLayers(); currLayer; currLayer = currLayer->next())
             list->append(cssValuePool().createValue(currLayer->blendMode()));
         return list.release();
     }
     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);
     case CSSPropertyBorderColor:
         return valuesForSidesShorthand(borderColorShorthand(), style, layoutObject, styledNode, allowVisitedStyle);
     case CSSPropertyBorderLeft:
         return valuesForShorthandProperty(borderLeftShorthand(), style, layoutObject, styledNode, allowVisitedStyle);
     case CSSPropertyBorderImage:
         return valueForNinePieceImage(style.borderImage(), style);
     case CSSPropertyBorderRadius:
@@ skipping 303 matching lines @@
     case CSSPropertyAll:
         return nullptr;
     default:
         break;
     }
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 }