CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/css/resolver/StyleBuilderConverter.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 29 matching lines @@
 #include "core/svg/SVGElement.h"
 #include "core/svg/SVGURIReference.h"
 #include "platform/transforms/RotateTransformOperation.h"
 #include "platform/transforms/ScaleTransformOperation.h"
 #include "platform/transforms/TranslateTransformOperation.h"
 
 namespace blink {
 
 namespace {
 
-static GridLength convertGridTrackBreadth(const StyleResolverState& state, CSSPrimitiveValue primitiveValue)
+static GridLength convertGridTrackBreadth(const StyleResolverState& state, const CSSPrimitiveValue& primitiveValue)
 {
     if (primitiveValue.getValueID() == CSSValueMinContent)
         return Length(MinContent);
 
     if (primitiveValue.getValueID() == CSSValueMaxContent)
         return Length(MaxContent);
 
     // Fractional unit.
     if (primitiveValue.isFlex())
         return GridLength(primitiveValue.getDoubleValue());
 
     return StyleBuilderConverter::convertLengthOrAuto(state, primitiveValue);
 }
 
 } // namespace
 
-PassRefPtr<StyleReflection> StyleBuilderConverter::convertBoxReflect(StyleResolverState& state, CSSValue value)
+PassRefPtr<StyleReflection> StyleBuilderConverter::convertBoxReflect(StyleResolverState& state, const CSSValue& value)
 {
     if (value.isPrimitiveValue()) {
         ASSERT(toCSSPrimitiveValue(value).getValueID() == CSSValueNone);
         return ComputedStyle::initialBoxReflect();
     }
 
     CSSReflectValue& reflectValue = toCSSReflectValue(value);
     RefPtr<StyleReflection> reflection = StyleReflection::create();
     reflection->setDirection(reflectValue.direction());
     reflection->setOffset(reflectValue.offset().convertToLength(state.cssToLengthConversionData()));
     NinePieceImage mask;
     mask.setMaskDefaults();
     CSSToStyleMap::mapNinePieceImage(state, CSSPropertyWebkitBoxReflect, reflectValue.mask(), mask);
     reflection->setMask(mask);
 
     return reflection.release();
 }
 
-Color StyleBuilderConverter::convertColor(StyleResolverState& state, CSSValue value, bool forVisitedLink)
+Color StyleBuilderConverter::convertColor(StyleResolverState& state, const CSSValue& value, bool forVisitedLink)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     return state.document().textLinkColors().colorFromPrimitiveValue(primitiveValue, state.style()->color(), forVisitedLink);
 }
 
-AtomicString StyleBuilderConverter::convertFragmentIdentifier(StyleResolverState& state, CSSValue value)
+AtomicString StyleBuilderConverter::convertFragmentIdentifier(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.isURI())
         return SVGURIReference::fragmentIdentifierFromIRIString(primitiveValue.getStringValue(), state.element()->treeScope());
     return nullAtom;
 }
 
-LengthBox StyleBuilderConverter::convertClip(StyleResolverState& state, CSSValue value)
+LengthBox StyleBuilderConverter::convertClip(StyleResolverState& state, const CSSValue& value)
 {
     Rect* rect = toCSSPrimitiveValue(value).getRectValue();
 
     return LengthBox(convertLengthOrAuto(state, rect->top()),
         convertLengthOrAuto(state, rect->right()),
         convertLengthOrAuto(state, rect->bottom()),
         convertLengthOrAuto(state, rect->left()));
 }
 
 static FontDescription::GenericFamilyType convertGenericFamily(CSSValueID valueID)
@@ skipping 11 matching lines @@
         return FontDescription::FantasyFamily;
     case CSSValueMonospace:
         return FontDescription::MonospaceFamily;
     case CSSValueWebkitPictograph:
         return FontDescription::PictographFamily;
     default:
         return FontDescription::NoFamily;
     }
 }
 
-static bool convertFontFamilyName(StyleResolverState& state, CSSPrimitiveValue primitiveValue,
+static bool convertFontFamilyName(StyleResolverState& state, const CSSPrimitiveValue& primitiveValue,
     FontDescription::GenericFamilyType& genericFamily, AtomicString& familyName)
 {
     if (primitiveValue.isCustomIdent()) {
         genericFamily = FontDescription::NoFamily;
         familyName = AtomicString(primitiveValue.getStringValue());
     } else if (state.document().settings()) {
         genericFamily = convertGenericFamily(primitiveValue.getValueID());
         familyName = state.fontBuilder().genericFontFamilyName(genericFamily);
     }
 
     return !familyName.isEmpty();
 }
 
-FontDescription::FamilyDescription StyleBuilderConverter::convertFontFamily(StyleResolverState& state, CSSValue value)
+FontDescription::FamilyDescription StyleBuilderConverter::convertFontFamily(StyleResolverState& state, const CSSValue& value)
 {
     ASSERT(value.isValueList());
 
     FontDescription::FamilyDescription desc(FontDescription::NoFamily);
     FontFamily* currFamily = nullptr;
 
     for (auto& family : toCSSValueList(value)) {
         FontDescription::GenericFamilyType genericFamily = FontDescription::NoFamily;
         AtomicString familyName;
 
@@ skipping 10 matching lines @@
 
         currFamily->setFamily(familyName);
 
         if (genericFamily != FontDescription::NoFamily)
             desc.genericFamily = genericFamily;
     }
 
     return desc;
 }
 
-PassRefPtr<FontFeatureSettings> StyleBuilderConverter::convertFontFeatureSettings(StyleResolverState& state, CSSValue value)
+PassRefPtr<FontFeatureSettings> StyleBuilderConverter::convertFontFeatureSettings(StyleResolverState& state, const CSSValue& value)
 {
     if (value.isPrimitiveValue() && toCSSPrimitiveValue(value).getValueID() == CSSValueNormal)
         return FontBuilder::initialFeatureSettings();
 
     CSSValueList& list = toCSSValueList(value);
     RefPtr<FontFeatureSettings> settings = FontFeatureSettings::create();
     int len = list.length();
     for (int i = 0; i < len; ++i) {
         CSSFontFeatureValue& feature = toCSSFontFeatureValue(list.item(i));
         settings->append(FontFeature(feature.tag(), feature.value()));
     }
     return settings;
 }
 
-static float computeFontSize(StyleResolverState& state, CSSPrimitiveValue primitiveValue, const FontDescription::Size& parentSize)
+static float computeFontSize(StyleResolverState& state, const CSSPrimitiveValue& primitiveValue, const FontDescription::Size& parentSize)
 {
     float em = state.parentStyle()->specifiedFontSize();
     float rem = state.rootElementStyle() ? state.rootElementStyle()->specifiedFontSize() : 1.0f;
     CSSToLengthConversionData::FontSizes fontSizes(em, rem, &state.parentStyle()->font());
     CSSToLengthConversionData::ViewportSize viewportSize(state.document().layoutView());
 
     CSSToLengthConversionData conversionData(state.style(), fontSizes, viewportSize, 1.0f);
     if (primitiveValue.isLength())
         return primitiveValue.computeLength<float>(conversionData);
     if (primitiveValue.isCalculatedPercentageWithLength())
         return primitiveValue.cssCalcValue()->toCalcValue(conversionData)->evaluate(parentSize.value);
 
     ASSERT_NOT_REACHED();
     return 0;
 }
 
-FontDescription::Size StyleBuilderConverter::convertFontSize(StyleResolverState& state, CSSValue value)
+FontDescription::Size StyleBuilderConverter::convertFontSize(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
 
     FontDescription::Size parentSize(0, 0.0f, false);
 
     // FIXME: Find out when parentStyle could be 0?
     if (state.parentStyle())
         parentSize = state.parentFontDescription().size();
 
     if (CSSValueID valueID = primitiveValue.getValueID()) {
         switch (valueID) {
         case CSSValueXxSmall:
@@ skipping 16 matching lines @@
     }
 
     bool parentIsAbsoluteSize = state.parentFontDescription().isAbsoluteSize();
 
     if (primitiveValue.isPercentage())
         return FontDescription::Size(0, (primitiveValue.getFloatValue() * parentSize.value / 100.0f), parentIsAbsoluteSize);
 
     return FontDescription::Size(0, computeFontSize(state, primitiveValue, parentSize), parentIsAbsoluteSize || !primitiveValue.isFontRelativeLength());
 }
 
-float StyleBuilderConverter::convertFontSizeAdjust(StyleResolverState& state, CSSValue value)
+float StyleBuilderConverter::convertFontSizeAdjust(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == CSSValueNone)
         return FontBuilder::initialSizeAdjust();
 
     ASSERT(primitiveValue.isNumber());
     return primitiveValue.getFloatValue();
 }
 
-FontWeight StyleBuilderConverter::convertFontWeight(StyleResolverState& state, CSSValue value)
+FontWeight StyleBuilderConverter::convertFontWeight(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     switch (primitiveValue.getValueID()) {
     case CSSValueBolder:
         return FontDescription::bolderWeight(state.parentStyle()->fontDescription().weight());
     case CSSValueLighter:
         return FontDescription::lighterWeight(state.parentStyle()->fontDescription().weight());
     default:
         return primitiveValue;
     }
 }
 
-FontDescription::VariantLigatures StyleBuilderConverter::convertFontVariantLigatures(StyleResolverState&, CSSValue value)
+FontDescription::VariantLigatures StyleBuilderConverter::convertFontVariantLigatures(StyleResolverState&, const CSSValue& value)
 {
     if (value.isValueList()) {
         FontDescription::VariantLigatures ligatures;
         CSSValueList& valueList = toCSSValueList(value);
         for (size_t i = 0; i < valueList.length(); ++i) {
-            CSSValue item = valueList.item(i);
-            CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(item);
+            const CSSValue& item = valueList.item(i);
+            const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(item);
             switch (primitiveValue.getValueID()) {
             case CSSValueNoCommonLigatures:
                 ligatures.common = FontDescription::DisabledLigaturesState;
                 break;
             case CSSValueCommonLigatures:
                 ligatures.common = FontDescription::EnabledLigaturesState;
                 break;
             case CSSValueNoDiscretionaryLigatures:
                 ligatures.discretionary = FontDescription::DisabledLigaturesState;
                 break;
@@ skipping 18 matching lines @@
             }
         }
         return ligatures;
     }
 
     ASSERT_WITH_SECURITY_IMPLICATION(value.isPrimitiveValue());
     ASSERT(toCSSPrimitiveValue(value).getValueID() == CSSValueNormal);
     return FontDescription::VariantLigatures();
 }
 
-EGlyphOrientation StyleBuilderConverter::convertGlyphOrientation(StyleResolverState&, CSSValue value)
+EGlyphOrientation StyleBuilderConverter::convertGlyphOrientation(StyleResolverState&, const CSSValue& value)
 {
     if (!value.isPrimitiveValue())
         return GO_0DEG;
 
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.primitiveType() != CSSPrimitiveValue::CSS_DEG)
         return GO_0DEG;
 
     float angle = fabsf(fmodf(primitiveValue.getFloatValue(), 360.0f));
 
     if (angle <= 45.0f || angle > 315.0f)
         return GO_0DEG;
     if (angle > 45.0f && angle <= 135.0f)
         return GO_90DEG;
     if (angle > 135.0f && angle <= 225.0f)
         return GO_180DEG;
     return GO_270DEG;
 }
 
-StyleSelfAlignmentData StyleBuilderConverter::convertSelfOrDefaultAlignmentData(StyleResolverState&, CSSValue value)
+StyleSelfAlignmentData StyleBuilderConverter::convertSelfOrDefaultAlignmentData(StyleResolverState&, const CSSValue& value)
 {
     StyleSelfAlignmentData alignmentData = ComputedStyle::initialSelfAlignment();
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (Pair* pairValue = primitiveValue.getPairValue()) {
-        if (toCSSPrimitiveValue(*pairValue->first()).getValueID() == CSSValueLegacy) {
+        if (pairValue->first().getValueID() == CSSValueLegacy) {
             alignmentData.setPositionType(LegacyPosition);
-            alignmentData.setPosition(toCSSPrimitiveValue(*pairValue->second()));
+            alignmentData.setPosition(pairValue->second());
         } else {
-            alignmentData.setPosition(toCSSPrimitiveValue(*pairValue->first()));
-            alignmentData.setOverflow(toCSSPrimitiveValue(*pairValue->second()));
+            alignmentData.setPosition(pairValue->first());
+            alignmentData.setOverflow(pairValue->second());
         }
     } else {
         alignmentData.setPosition(primitiveValue);
     }
     return alignmentData;
 }
 
-StyleContentAlignmentData StyleBuilderConverter::convertContentAlignmentData(StyleResolverState&, CSSValue value)
+StyleContentAlignmentData StyleBuilderConverter::convertContentAlignmentData(StyleResolverState&, const CSSValue& value)
 {
     StyleContentAlignmentData alignmentData = ComputedStyle::initialContentAlignment();
     CSSContentDistributionValue& contentValue = toCSSContentDistributionValue(value);
     if (contentValue.distribution().getValueID() != CSSValueInvalid)
         alignmentData.setDistribution(contentValue.distribution());
     if (contentValue.position().getValueID() != CSSValueInvalid)
         alignmentData.setPosition(contentValue.position());
     if (contentValue.overflow().getValueID() != CSSValueInvalid)
         alignmentData.setOverflow(contentValue.overflow());
     return alignmentData;
 }
 
-GridAutoFlow StyleBuilderConverter::convertGridAutoFlow(StyleResolverState&, CSSValue value)
+GridAutoFlow StyleBuilderConverter::convertGridAutoFlow(StyleResolverState&, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
 
     ASSERT(list.length() >= 1);
-    CSSPrimitiveValue first = toCSSPrimitiveValue(list.item(0));
+    const CSSPrimitiveValue& first = toCSSPrimitiveValue(list.item(0));
     NullableCSSValue second = list.length() == 2 ? NullableCSSValue(list.item(1)) : nullptr;
 
     switch (first.getValueID()) {
     case CSSValueRow:
         if (second && toCSSPrimitiveValue(*second).getValueID() == CSSValueDense)
             return AutoFlowRowDense;
         return AutoFlowRow;
     case CSSValueColumn:
         if (second && toCSSPrimitiveValue(*second).getValueID() == CSSValueDense)
             return AutoFlowColumnDense;
         return AutoFlowColumn;
     case CSSValueDense:
         if (second && toCSSPrimitiveValue(*second).getValueID() == CSSValueColumn)
             return AutoFlowColumnDense;
         return AutoFlowRowDense;
     default:
         ASSERT_NOT_REACHED();
         return ComputedStyle::initialGridAutoFlow();
     }
 }
 
-GridPosition StyleBuilderConverter::convertGridPosition(StyleResolverState&, CSSValue value)
+GridPosition StyleBuilderConverter::convertGridPosition(StyleResolverState&, const CSSValue& value)
 {
     // We accept the specification's grammar:
     // 'auto' | [ <integer> || <custom-ident> ] | [ span && [ <integer> || <custom-ident> ] ] | <custom-ident>
 
     GridPosition position;
 
     if (value.isPrimitiveValue()) {
-        CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+        const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
         // We translate <custom-ident> to <string> during parsing as it
         // makes handling it more simple.
         if (primitiveValue.isCustomIdent()) {
             position.setNamedGridArea(primitiveValue.getStringValue());
             return position;
         }
 
         ASSERT(primitiveValue.getValueID() == CSSValueAuto);
         return position;
     }
@@ skipping 27 matching lines @@
 
     ASSERT(it == values.end());
     if (isSpanPosition)
         position.setSpanPosition(gridLineNumber, gridLineName);
     else
         position.setExplicitPosition(gridLineNumber, gridLineName);
 
     return position;
 }
 
-GridTrackSize StyleBuilderConverter::convertGridTrackSize(StyleResolverState& state, CSSValue value)
+GridTrackSize StyleBuilderConverter::convertGridTrackSize(StyleResolverState& state, const CSSValue& value)
 {
     if (value.isPrimitiveValue())
         return GridTrackSize(convertGridTrackBreadth(state, toCSSPrimitiveValue(value)));
 
     CSSFunctionValue& minmaxFunction = toCSSFunctionValue(value);
     ASSERT_WITH_SECURITY_IMPLICATION(minmaxFunction.length() == 2);
     GridLength minTrackBreadth(convertGridTrackBreadth(state, toCSSPrimitiveValue(minmaxFunction.item(0))));
     GridLength maxTrackBreadth(convertGridTrackBreadth(state, toCSSPrimitiveValue(minmaxFunction.item(1))));
     return GridTrackSize(minTrackBreadth, maxTrackBreadth);
 }
 
-bool StyleBuilderConverter::convertGridTrackList(CSSValue value, Vector<GridTrackSize>& trackSizes, NamedGridLinesMap& namedGridLines, OrderedNamedGridLines& orderedNamedGridLines, StyleResolverState& state)
+bool StyleBuilderConverter::convertGridTrackList(const CSSValue& value, Vector<GridTrackSize>& trackSizes, NamedGridLinesMap& namedGridLines, OrderedNamedGridLines& orderedNamedGridLines, StyleResolverState& state)
 {
     // Handle 'none'.
     if (value.isPrimitiveValue()) {
-        CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+        const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
         return primitiveValue.getValueID() == CSSValueNone;
     }
 
     if (!value.isValueList())
         return false;
 
     size_t currentNamedGridLine = 0;
     for (auto& currValue : toCSSValueList(value)) {
         if (currValue.isGridLineNamesValue()) {
             for (auto& namedGridLineValue : toCSSGridLineNamesValue(currValue)) {
@@ skipping 46 matching lines @@
             std::sort(startResult.storedValue->value.begin(), startResult.storedValue->value.end());
         }
         {
             NamedGridLinesMap::AddResult endResult = namedGridLines.add(namedGridAreaEntry.key + "-end", Vector<size_t>());
             endResult.storedValue->value.append(areaSpan.resolvedFinalPosition.toInt() + 1);
             std::sort(endResult.storedValue->value.begin(), endResult.storedValue->value.end());
         }
     }
 }
 
-Length StyleBuilderConverter::convertLength(const StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertLength(const StyleResolverState& state, const CSSValue& value)
 {
     return toCSSPrimitiveValue(value).convertToLength(state.cssToLengthConversionData());
 }
 
-UnzoomedLength StyleBuilderConverter::convertUnzoomedLength(const StyleResolverState& state, CSSValue value)
+UnzoomedLength StyleBuilderConverter::convertUnzoomedLength(const StyleResolverState& state, const CSSValue& value)
 {
     return UnzoomedLength(toCSSPrimitiveValue(value).convertToLength(state.cssToLengthConversionData().copyWithAdjustedZoom(1.0f)));
 }
 
-Length StyleBuilderConverter::convertLengthOrAuto(const StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertLengthOrAuto(const StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == CSSValueAuto)
         return Length(Auto);
     return primitiveValue.convertToLength(state.cssToLengthConversionData());
 }
 
-Length StyleBuilderConverter::convertLengthSizing(StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertLengthSizing(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     switch (primitiveValue.getValueID()) {
     case CSSValueInvalid:
         return convertLength(state, value);
     case CSSValueIntrinsic:
         return Length(Intrinsic);
     case CSSValueMinIntrinsic:
         return Length(MinIntrinsic);
     case CSSValueMinContent:
     case CSSValueWebkitMinContent:
         return Length(MinContent);
     case CSSValueMaxContent:
     case CSSValueWebkitMaxContent:
         return Length(MaxContent);
     case CSSValueWebkitFillAvailable:
         return Length(FillAvailable);
     case CSSValueWebkitFitContent:
         return Length(FitContent);
     case CSSValueAuto:
         return Length(Auto);
     default:
         ASSERT_NOT_REACHED();
         return Length();
     }
 }
 
-Length StyleBuilderConverter::convertLengthMaxSizing(StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertLengthMaxSizing(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == CSSValueNone)
         return Length(MaxSizeNone);
     return convertLengthSizing(state, value);
 }
 
-TabSize StyleBuilderConverter::convertLengthOrTabSpaces(StyleResolverState& state, CSSValue value)
+TabSize StyleBuilderConverter::convertLengthOrTabSpaces(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.isNumber())
         return TabSize(primitiveValue.getIntValue());
     return TabSize(primitiveValue.computeLength<float>(state.cssToLengthConversionData()));
 }
 
-LineBoxContain StyleBuilderConverter::convertLineBoxContain(StyleResolverState&, CSSValue value)
+LineBoxContain StyleBuilderConverter::convertLineBoxContain(StyleResolverState&, const CSSValue& value)
 {
     if (value.isPrimitiveValue()) {
         ASSERT(toCSSPrimitiveValue(value).getValueID() == CSSValueNone);
         return LineBoxContainNone;
     }
 
     return toCSSLineBoxContainValue(value).value();
 }
 
 static CSSToLengthConversionData lineHeightToLengthConversionData(StyleResolverState& state)
 {
     float multiplier = state.style()->effectiveZoom();
     if (LocalFrame* frame = state.document().frame())
         multiplier *= frame->textZoomFactor();
     return state.cssToLengthConversionData().copyWithAdjustedZoom(multiplier);
 }
 
-Length StyleBuilderConverter::convertLineHeight(StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertLineHeight(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
 
     if (primitiveValue.isLength())
         return primitiveValue.computeLength<Length>(lineHeightToLengthConversionData(state));
     if (primitiveValue.isPercentage())
         return Length((state.style()->computedFontSize() * primitiveValue.getIntValue()) / 100.0, Fixed);
     if (primitiveValue.isNumber())
         return Length(primitiveValue.getDoubleValue() * 100.0, Percent);
     if (primitiveValue.isCalculated()) {
         Length zoomedLength = Length(primitiveValue.cssCalcValue()->toCalcValue(lineHeightToLengthConversionData(state)));
         return Length(valueForLength(zoomedLength, state.style()->fontSize()), Fixed);
     }
 
     ASSERT(primitiveValue.getValueID() == CSSValueNormal);
     return ComputedStyle::initialLineHeight();
 }
 
-float StyleBuilderConverter::convertNumberOrPercentage(StyleResolverState& state, CSSValue value)
+float StyleBuilderConverter::convertNumberOrPercentage(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     ASSERT(primitiveValue.isNumber() || primitiveValue.isPercentage());
     if (primitiveValue.isNumber())
         return primitiveValue.getFloatValue();
     return primitiveValue.getFloatValue() / 100.0f;
 }
 
 template <CSSValueID cssValueFor0, CSSValueID cssValueFor100>
-static Length convertPositionLength(StyleResolverState& state, CSSPrimitiveValue primitiveValue)
+static Length convertPositionLength(StyleResolverState& state, const CSSPrimitiveValue& primitiveValue)
 {
     if (Pair* pair = primitiveValue.getPairValue()) {
-        Length length = StyleBuilderConverter::convertLength(state, CSSValue(*pair->second()));
-        if (toCSSPrimitiveValue(*pair->first()).getValueID() == cssValueFor0)
+        Length length = StyleBuilderConverter::convertLength(state, pair->second());
+        if (pair->first().getValueID() == cssValueFor0)
             return length;
-        ASSERT(toCSSPrimitiveValue(*pair->first()).getValueID() == cssValueFor100);
+        ASSERT(pair->first().getValueID() == cssValueFor100);
         return length.subtractFromOneHundredPercent();
     }
 
     return StyleBuilderConverter::convertLength(state, primitiveValue);
 }
 
-LengthPoint StyleBuilderConverter::convertPosition(StyleResolverState& state, CSSValue value)
+LengthPoint StyleBuilderConverter::convertPosition(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     Pair* pair = primitiveValue.getPairValue();
     return LengthPoint(
-        convertPositionLength<CSSValueLeft, CSSValueRight>(state, toCSSPrimitiveValue(*pair->first())),
-        convertPositionLength<CSSValueTop, CSSValueBottom>(state, toCSSPrimitiveValue(*pair->second()))
+        convertPositionLength<CSSValueLeft, CSSValueRight>(state, pair->first()),
+        convertPositionLength<CSSValueTop, CSSValueBottom>(state, pair->second())
     );
 }
 
-static float convertPerspectiveLength(StyleResolverState& state, CSSPrimitiveValue primitiveValue)
+static float convertPerspectiveLength(StyleResolverState& state, const CSSPrimitiveValue& primitiveValue)
 {
     return std::max(primitiveValue.computeLength<float>(state.cssToLengthConversionData()), 0.0f);
 }
 
-float StyleBuilderConverter::convertPerspective(StyleResolverState& state, CSSValue value)
+float StyleBuilderConverter::convertPerspective(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
 
     if (primitiveValue.getValueID() == CSSValueNone)
         return ComputedStyle::initialPerspective();
     return convertPerspectiveLength(state, primitiveValue);
 }
 
 template <CSSValueID cssValueFor0, CSSValueID cssValueFor100>
-static Length convertOriginLength(StyleResolverState& state, CSSPrimitiveValue primitiveValue)
+static Length convertOriginLength(StyleResolverState& state, const CSSPrimitiveValue& primitiveValue)
 {
     if (primitiveValue.isValueID()) {
         switch (primitiveValue.getValueID()) {
         case cssValueFor0:
             return Length(0, Percent);
         case cssValueFor100:
             return Length(100, Percent);
         case CSSValueCenter:
             return Length(50, Percent);
         default:
             ASSERT_NOT_REACHED();
         }
     }
 
     return StyleBuilderConverter::convertLength(state, CSSValue(primitiveValue));
 }
 
-LengthPoint StyleBuilderConverter::convertPerspectiveOrigin(StyleResolverState& state, CSSValue value)
+LengthPoint StyleBuilderConverter::convertPerspectiveOrigin(StyleResolverState& state, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
     ASSERT(list.length() == 2);
 
-    CSSPrimitiveValue primitiveValueX = toCSSPrimitiveValue(list.item(0));
-    CSSPrimitiveValue primitiveValueY = toCSSPrimitiveValue(list.item(1));
+    const CSSPrimitiveValue& primitiveValueX = toCSSPrimitiveValue(list.item(0));
+    const CSSPrimitiveValue& primitiveValueY = toCSSPrimitiveValue(list.item(1));
 
     return LengthPoint(
         convertOriginLength<CSSValueLeft, CSSValueRight>(state, primitiveValueX),
         convertOriginLength<CSSValueTop, CSSValueBottom>(state, primitiveValueY)
     );
 }
 
-EPaintOrder StyleBuilderConverter::convertPaintOrder(StyleResolverState&, CSSValue cssPaintOrder)
+EPaintOrder StyleBuilderConverter::convertPaintOrder(StyleResolverState&, const CSSValue& cssPaintOrder)
 {
     if (cssPaintOrder.isValueList()) {
         int paintOrder = 0;
         const CSSValueList& list = toCSSValueList(cssPaintOrder);
         for (size_t i = 0; i < list.length(); ++i) {
             EPaintOrderType paintOrderType = PT_NONE;
             switch (toCSSPrimitiveValue(list.item(i)).getValueID()) {
             case CSSValueFill:
                 paintOrderType = PT_FILL;
                 break;
             case CSSValueStroke:
                 paintOrderType = PT_STROKE;
                 break;
             case CSSValueMarkers:
                 paintOrderType = PT_MARKERS;
                 break;
             default:
                 ASSERT_NOT_REACHED();
                 break;
             }
 
             paintOrder |= (paintOrderType << kPaintOrderBitwidth*i);
         }
         return (EPaintOrder)paintOrder;
     }
 
     return PO_NORMAL;
 }
 
-Length StyleBuilderConverter::convertQuirkyLength(StyleResolverState& state, CSSValue value)
+Length StyleBuilderConverter::convertQuirkyLength(StyleResolverState& state, const CSSValue& value)
 {
     Length length = convertLengthOrAuto(state, value);
     // This is only for margins which use __qem
     length.setQuirk(toCSSPrimitiveValue(value).isQuirkValue());
     return length;
 }
 
-PassRefPtr<QuotesData> StyleBuilderConverter::convertQuotes(StyleResolverState&, CSSValue value)
+PassRefPtr<QuotesData> StyleBuilderConverter::convertQuotes(StyleResolverState&, const CSSValue& value)
 {
     if (value.isValueList()) {
         CSSValueList& list = toCSSValueList(value);
         RefPtr<QuotesData> quotes = QuotesData::create();
         for (size_t i = 0; i < list.length(); i += 2) {
-            CSSValue first = list.item(i);
-            CSSValue second = list.item(i + 1);
+            const CSSValue& first = list.item(i);
+            const CSSValue& second = list.item(i + 1);
             String startQuote = toCSSPrimitiveValue(first).getStringValue();
             String endQuote = toCSSPrimitiveValue(second).getStringValue();
             quotes->addPair(std::make_pair(startQuote, endQuote));
         }
         return quotes.release();
     }
     // FIXME: We should assert we're a primitive value with valueID = CSSValueNone
     return QuotesData::create();
 }
 
-LengthSize StyleBuilderConverter::convertRadius(StyleResolverState& state, CSSValue value)
+LengthSize StyleBuilderConverter::convertRadius(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     Pair* pair = primitiveValue.getPairValue();
-    Length radiusWidth = toCSSPrimitiveValue(*pair->first()).convertToLength(state.cssToLengthConversionData());
-    Length radiusHeight = toCSSPrimitiveValue(*pair->second()).convertToLength(state.cssToLengthConversionData());
+    Length radiusWidth = pair->first().convertToLength(state.cssToLengthConversionData());
+    Length radiusHeight = pair->second().convertToLength(state.cssToLengthConversionData());
     float width = radiusWidth.value();
     float height = radiusHeight.value();
     ASSERT(width >= 0 && height >= 0);
     if (width <= 0 || height <= 0)
         return LengthSize(Length(0, Fixed), Length(0, Fixed));
     return LengthSize(radiusWidth, radiusHeight);
 }
 
-PassRefPtr<ShadowList> StyleBuilderConverter::convertShadow(StyleResolverState& state, CSSValue value)
+PassRefPtr<ShadowList> StyleBuilderConverter::convertShadow(StyleResolverState& state, const CSSValue& value)
 {
     if (value.isPrimitiveValue()) {
         ASSERT(toCSSPrimitiveValue(value).getValueID() == CSSValueNone);
         return PassRefPtr<ShadowList>();
     }
 
     const CSSValueList& valueList = toCSSValueList(value);
     size_t shadowCount = valueList.length();
     ShadowDataVector shadows;
     for (size_t i = 0; i < shadowCount; ++i) {
         const CSSShadowValue& item = toCSSShadowValue(valueList.item(i));
         float x = toCSSPrimitiveValue(*item.x).computeLength<float>(state.cssToLengthConversionData());
         float y = toCSSPrimitiveValue(*item.y).computeLength<float>(state.cssToLengthConversionData());
         float blur = item.blur ? toCSSPrimitiveValue(*item.blur).computeLength<float>(state.cssToLengthConversionData()) : 0;
         float spread = item.spread ? toCSSPrimitiveValue(*item.spread).computeLength<float>(state.cssToLengthConversionData()) : 0;
         ShadowStyle shadowStyle = item.style && toCSSPrimitiveValue(*item.style).getValueID() == CSSValueInset ? Inset : Normal;
         StyleColor color = StyleColor::currentColor();
         if (item.color)
             color = convertStyleColor(state, CSSValue(*item.color));
         shadows.append(ShadowData(FloatPoint(x, y), blur, spread, shadowStyle, color));
     }
     return ShadowList::adopt(shadows);
 }
 
-PassRefPtr<ShapeValue> StyleBuilderConverter::convertShapeValue(StyleResolverState& state, CSSValue value)
+PassRefPtr<ShapeValue> StyleBuilderConverter::convertShapeValue(StyleResolverState& state, const CSSValue& value)
 {
     if (value.isPrimitiveValue()) {
         ASSERT(toCSSPrimitiveValue(value).getValueID() == CSSValueNone);
         return nullptr;
     }
 
     if (value.isImageValue() || value.isImageGeneratorValue() || value.isImageSetValue())
         return ShapeValue::createImageValue(state.styleImage(CSSPropertyShapeOutside, value));
 
     RefPtr<BasicShape> shape;
     CSSBoxType cssBox = BoxMissing;
     CSSValueList& valueList = toCSSValueList(value);
     for (unsigned i = 0; i < valueList.length(); ++i) {
-        CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(valueList.item(i));
+        const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(valueList.item(i));
         if (primitiveValue.isShape())
             shape = basicShapeForValue(state, primitiveValue.getShapeValue());
         else
             cssBox = CSSBoxType(primitiveValue);
     }
 
     if (shape)
         return ShapeValue::createShapeValue(shape.release(), cssBox);
 
     ASSERT(cssBox != BoxMissing);
     return ShapeValue::createBoxShapeValue(cssBox);
 }
 
-float StyleBuilderConverter::convertSpacing(StyleResolverState& state, CSSValue value)
+float StyleBuilderConverter::convertSpacing(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == CSSValueNormal)
         return 0;
     return primitiveValue.computeLength<float>(state.cssToLengthConversionData());
 }
 
-PassRefPtr<SVGDashArray> StyleBuilderConverter::convertStrokeDasharray(StyleResolverState& state, CSSValue value)
+PassRefPtr<SVGDashArray> StyleBuilderConverter::convertStrokeDasharray(StyleResolverState& state, const CSSValue& value)
 {
     if (!value.isValueList())
         return SVGComputedStyle::initialStrokeDashArray();
 
     CSSValueList& dashes = toCSSValueList(value);
 
     RefPtr<SVGDashArray> array = SVGDashArray::create();
     size_t length = dashes.length();
     for (size_t i = 0; i < length; ++i) {
-        CSSValue currValue = dashes.item(i);
+        const CSSValue& currValue = dashes.item(i);
         if (!currValue.isPrimitiveValue())
             continue;
 
         array->append(convertLength(state, currValue));
     }
 
     return array.release();
 }
 
-StyleColor StyleBuilderConverter::convertStyleColor(StyleResolverState& state, CSSValue value, bool forVisitedLink)
+StyleColor StyleBuilderConverter::convertStyleColor(StyleResolverState& state, const CSSValue& value, bool forVisitedLink)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == CSSValueCurrentcolor)
         return StyleColor::currentColor();
     return state.document().textLinkColors().colorFromPrimitiveValue(primitiveValue, Color(), forVisitedLink);
 }
 
-float StyleBuilderConverter::convertTextStrokeWidth(StyleResolverState& state, CSSValue value)
+float StyleBuilderConverter::convertTextStrokeWidth(StyleResolverState& state, const CSSValue& value)
 {
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID()) {
         float multiplier = convertLineWidth<float>(state, value);
         return CSSPrimitiveValue::create(multiplier / 48, CSSPrimitiveValue::CSS_EMS).computeLength<float>(state.cssToLengthConversionData());
     }
     return primitiveValue.computeLength<float>(state.cssToLengthConversionData());
 }
 
-TransformOrigin StyleBuilderConverter::convertTransformOrigin(StyleResolverState& state, CSSValue value)
+TransformOrigin StyleBuilderConverter::convertTransformOrigin(StyleResolverState& state, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
     ASSERT(list.length() == 3);
 
-    CSSPrimitiveValue primitiveValueX = toCSSPrimitiveValue(list.item(0));
-    CSSPrimitiveValue primitiveValueY = toCSSPrimitiveValue(list.item(1));
+    const CSSPrimitiveValue& primitiveValueX = toCSSPrimitiveValue(list.item(0));
+    const CSSPrimitiveValue& primitiveValueY = toCSSPrimitiveValue(list.item(1));
 
     return TransformOrigin(
         convertOriginLength<CSSValueLeft, CSSValueRight>(state, primitiveValueX),
         convertOriginLength<CSSValueTop, CSSValueBottom>(state, primitiveValueY),
         StyleBuilderConverter::convertComputedLength<float>(state, list.item(2))
     );
 }
 
-ScrollSnapPoints StyleBuilderConverter::convertSnapPoints(StyleResolverState& state, CSSValue value)
+ScrollSnapPoints StyleBuilderConverter::convertSnapPoints(StyleResolverState& state, const CSSValue& value)
 {
     // Handles: none | repeat(<length>)
     ScrollSnapPoints points;
     points.hasRepeat = false;
 
     if (!value.isFunctionValue())
         return points;
 
     CSSFunctionValue& repeatFunction = toCSSFunctionValue(value);
     ASSERT_WITH_SECURITY_IMPLICATION(repeatFunction.length() == 1);
     points.repeatOffset = convertLength(state, repeatFunction.item(0));
     points.hasRepeat = true;
 
     return points;
 }
 
-Vector<LengthPoint> StyleBuilderConverter::convertSnapCoordinates(StyleResolverState& state, CSSValue value)
+Vector<LengthPoint> StyleBuilderConverter::convertSnapCoordinates(StyleResolverState& state, const CSSValue& value)
 {
     // Handles: none | <position>#
     Vector<LengthPoint> coordinates;
 
     if (!value.isValueList())
         return coordinates;
 
     CSSValueList& valueList = toCSSValueList(value);
     coordinates.reserveInitialCapacity(valueList.length());
     for (auto& snapCoordinate : valueList) {
         coordinates.uncheckedAppend(convertPosition(state, snapCoordinate));
     }
 
     return coordinates;
 }
 
-PassRefPtr<TranslateTransformOperation> StyleBuilderConverter::convertTranslate(StyleResolverState& state, CSSValue value)
+PassRefPtr<TranslateTransformOperation> StyleBuilderConverter::convertTranslate(StyleResolverState& state, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
     ASSERT(list.length() <= 3);
     Length tx = convertLength(state, list.item(0));
     Length ty(0, Fixed);
     double tz = 0;
     if (list.length() >= 2)
         ty = convertLength(state, list.item(1));
     if (list.length() == 3)
         tz = toCSSPrimitiveValue(list.item(2)).getDoubleValue();
 
     return TranslateTransformOperation::create(tx, ty, tz, TransformOperation::Translate3D);
 }
 
-PassRefPtr<RotateTransformOperation> StyleBuilderConverter::convertRotate(StyleResolverState& state, CSSValue value)
+PassRefPtr<RotateTransformOperation> StyleBuilderConverter::convertRotate(StyleResolverState& state, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
     ASSERT(list.length() == 1 || list.length() == 4);
     double angle = toCSSPrimitiveValue(list.item(0)).computeDegrees();
     double x = 0;
     double y = 0;
     double z = 1;
     if (list.length() == 4) {
         x = toCSSPrimitiveValue(list.item(1)).getDoubleValue();
         y = toCSSPrimitiveValue(list.item(2)).getDoubleValue();
         z = toCSSPrimitiveValue(list.item(3)).getDoubleValue();
     }
 
     return RotateTransformOperation::create(x, y, z, angle, TransformOperation::Rotate3D);
 }
 
-PassRefPtr<ScaleTransformOperation> StyleBuilderConverter::convertScale(StyleResolverState& state, CSSValue value)
+PassRefPtr<ScaleTransformOperation> StyleBuilderConverter::convertScale(StyleResolverState& state, const CSSValue& value)
 {
     CSSValueList& list = toCSSValueList(value);
     ASSERT(list.length() <= 3);
     double sx = toCSSPrimitiveValue(list.item(0)).getDoubleValue();
     double sy = sx;
     double sz = 1;
     if (list.length() >= 2)
         sy = toCSSPrimitiveValue(list.item(1)).getDoubleValue();
     if (list.length() == 3)
         sz = toCSSPrimitiveValue(list.item(2)).getDoubleValue();
 
     return ScaleTransformOperation::create(sx, sy, sz, TransformOperation::Scale3D);
 }
 
 } // namespace blink