Add CSS parser support for the snap-height property

This patch adds CSS parser support for the snap-height property, behind
the CSSSnapSize runtime flag.

Supporting layout will be in following patches.

A test was imported from csswg-test and was marked as failure. This
patch makes the test pass.

Spec: https://drafts.csswg.org/css-snap-size/
Dashboard: https://www.chromestatus.com/features/5734273533345792

BUG=586413
TEST=imported/csswg-test/css-snap-size-1/snap-height-parsing-001.html

Review URL: https://codereview.chromium.org/1696373003

Cr-Commit-Position: refs/heads/master@{#376051}

third_party/WebKit/LayoutTests/fast/css/getComputedStyle/computed-style-listing-expected.txt

@@ -249,6 +249,7 @@ shape-image-threshold: 0
 shape-margin: 0px
 shape-outside: none
 shape-rendering: auto
+snap-height: 0px
 speak: normal
 stop-color: rgb(0, 0, 0)
 stop-opacity: 1

third_party/WebKit/LayoutTests/fast/css/getComputedStyle/computed-style-without-renderer-listing-expected.txt

@@ -249,6 +249,7 @@ shape-image-threshold: 0
 shape-margin: 0px
 shape-outside: none
 shape-rendering: auto
+snap-height: 0px
 speak: normal
 stop-color: rgb(0, 0, 0)
 stop-opacity: 1

third_party/WebKit/LayoutTests/imported/csswg-test/css-snap-size-1/snap-height-parsing-001-expected.txt

-This is a testharness.js-based test.
-FAIL initial value assert_equals: expected (string) "0px" but got (undefined) undefined
-FAIL snap-height: 20px 60 assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height should inherit assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: initial assert_equals: expected (string) "0px" but got (undefined) undefined
-FAIL snap-height: initial; snap-height: inherit assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: 40px assert_equals: expected (string) "40px" but got (undefined) undefined
-FAIL snap-height: 0 assert_equals: expected (string) "0px" but got (undefined) undefined
-FAIL snap-height: 1 assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: -1px assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: 40px -1 assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: 40px 0 assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL snap-height: 40px 101 assert_equals: expected (string) "20px 60" but got (undefined) undefined
-FAIL Computed value must be the absolute length Cannot read property 'slice' of undefined
-Harness: the test ran to completion.
-

third_party/WebKit/LayoutTests/svg/css/getComputedStyle-listing-expected.txt

@@ -249,6 +249,7 @@ shape-image-threshold: 0
 shape-margin: 0px
 shape-outside: none
 shape-rendering: auto
+snap-height: 0px
 speak: normal
 stop-color: rgb(0, 0, 0)
 stop-opacity: 1

third_party/WebKit/LayoutTests/webexposed/css-properties-as-js-properties-expected.txt

@@ -229,6 +229,7 @@ shapeMargin
 shapeOutside
 shapeRendering
 size
+snapHeight
 speak
 src
 stopColor

third_party/WebKit/Source/core/css/CSSComputedStyleDeclaration.cpp

@@ -154,6 +154,7 @@ static const CSSPropertyID staticComputableProperties[] = {
     CSSPropertyResize,
     CSSPropertyRight,
     CSSPropertyScrollBehavior,
+    CSSPropertySnapHeight,
     CSSPropertySpeak,
     CSSPropertyTableLayout,
     CSSPropertyTabSize,

third_party/WebKit/Source/core/css/CSSProperties.in

@@ -271,6 +271,7 @@ shape-margin interpolable, converter=convertLength
 shape-outside interpolable, converter=convertShapeValue
 shape-rendering inherited, svg
 size custom_all
+snap-height runtime_flag=CSSSnapSize, inherited, custom_all
 speak inherited
 stop-color interpolable, svg, converter=convertColor
 stop-opacity interpolable, svg, converter=convertNumberOrPercentage

third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp

@@ -2697,6 +2697,15 @@ PassRefPtrWillBeRawPtr<CSSValue> ComputedStyleCSSValueMapping::get(CSSPropertyID
         ASSERT(list->length());
         return list.release();
     }
+    case CSSPropertySnapHeight: {
+        if (!style.snapHeightUnit())
+            return cssValuePool().createValue(0, CSSPrimitiveValue::UnitType::Pixels);
+        RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+        list->append(cssValuePool().createValue(style.snapHeightUnit(), CSSPrimitiveValue::UnitType::Pixels));
+        if (style.snapHeightPosition())
+            list->append(cssValuePool().createValue(style.snapHeightPosition(), CSSPrimitiveValue::UnitType::Integer));
+        return list.release();
+    }
     case CSSPropertyVariable:
         // Variables are retrieved via get(AtomicString).
         ASSERT_NOT_REACHED();

third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

@@ -1289,6 +1289,23 @@ static PassRefPtrWillBeRawPtr<CSSValueList> consumeSize(CSSParserTokenRange& ran
     return result.release();
 }
 
+static PassRefPtrWillBeRawPtr<CSSValue> consumeSnapHeight(CSSParserTokenRange& range, CSSParserMode cssParserMode)
+{
+    RefPtrWillBeRawPtr<CSSPrimitiveValue> unit = consumeLength(range, cssParserMode, ValueRangeNonNegative);
+    if (!unit)
+        return nullptr;
+    RefPtrWillBeRawPtr<CSSValueList> list = CSSValueList::createSpaceSeparated();
+    list->append(unit.release());
+
+    if (RefPtrWillBeRawPtr<CSSPrimitiveValue> position = consumePositiveInteger(range)) {
+        if (position->getIntValue() > 100)
+            return nullptr;
+        list->append(position.release());
+    }
+
+    return list.release();
+}
+
 static PassRefPtrWillBeRawPtr<CSSValue> consumeTextIndent(CSSParserTokenRange& range, CSSParserMode cssParserMode)
 {
     // [ <length> | <percentage> ] && hanging? && each-line?
@@ -3425,6 +3442,8 @@ PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseSingleValue(CSSProperty
         return consumeCounter(m_range, m_context.mode(), property == CSSPropertyCounterIncrement ? 1 : 0);
     case CSSPropertySize:
         return consumeSize(m_range, m_context.mode());
+    case CSSPropertySnapHeight:
+        return consumeSnapHeight(m_range, m_context.mode());
     case CSSPropertyTextIndent:
         return consumeTextIndent(m_range, m_context.mode());
     case CSSPropertyMaxWidth:

third_party/WebKit/Source/core/css/resolver/StyleBuilderCustom.cpp

@@ -374,6 +374,40 @@ void StyleBuilderFunctions::applyValueCSSPropertySize(StyleResolverState& state,
     state.style()->setPageSize(size);
 }
 
+void StyleBuilderFunctions::applyInitialCSSPropertySnapHeight(StyleResolverState& state)
+{
+    state.style()->setSnapHeightUnit(0);
+    state.style()->setSnapHeightPosition(0);
+}
+
+void StyleBuilderFunctions::applyInheritCSSPropertySnapHeight(StyleResolverState& state)
+{
+    state.style()->setSnapHeightUnit(state.parentStyle()->snapHeightUnit());
+    state.style()->setSnapHeightPosition(state.parentStyle()->snapHeightPosition());
+}
+
+void StyleBuilderFunctions::applyValueCSSPropertySnapHeight(StyleResolverState& state, CSSValue* value)
+{
+    CSSValueList* list = toCSSValueList(value);
+    CSSPrimitiveValue* first = toCSSPrimitiveValue(list->item(0));
+    ASSERT(first->isLength());
+    int unit = first->computeLength<int>(state.cssToLengthConversionData());
+    ASSERT(unit >= 0);
+    state.style()->setSnapHeightUnit(clampTo<uint8_t>(unit));
+
+    if (list->length() == 1) {
+        state.style()->setSnapHeightPosition(0);
+        return;
+    }
+
+    ASSERT(list->length() == 2);
+    CSSPrimitiveValue* second = toCSSPrimitiveValue(list->item(1));
+    ASSERT(second->isNumber());
+    int position = second->getIntValue();
+    ASSERT(position > 0 && position <= 100);
+    state.style()->setSnapHeightPosition(position);
+}
+
 void StyleBuilderFunctions::applyValueCSSPropertyTextAlign(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);

third_party/WebKit/Source/core/frame/UseCounter.cpp

@@ -551,6 +551,7 @@ int UseCounter::mapCSSPropertyIdToCSSSampleIdForHistogram(int id)
     case CSSPropertyFontDisplay: return 516;
     case CSSPropertyContain: return 517;
     case CSSPropertyD: return 518;
+    case CSSPropertySnapHeight: return 519;
 
     // 1. Add new features above this line (don't change the assigned numbers of the existing
     // items).
@@ -567,7 +568,7 @@ int UseCounter::mapCSSPropertyIdToCSSSampleIdForHistogram(int id)
     return 0;
 }
 
-static int maximumCSSSampleId() { return 518; }
+static int maximumCSSSampleId() { return 519; }
 
 static EnumerationHistogram& featureObserverHistogram()
 {

third_party/WebKit/Source/core/style/ComputedStyle.h

@@ -935,6 +935,9 @@ public:
     TextCombine textCombine() const { return static_cast<TextCombine>(rareInheritedData->m_textCombine); }
     bool hasTextCombine() const { return textCombine() != TextCombineNone; }
 
+    uint8_t snapHeightPosition() const { return rareInheritedData->m_snapHeightPosition; }
+    uint8_t snapHeightUnit() const { return rareInheritedData->m_snapHeightUnit; }
+
     TabSize tabSize() const { return rareInheritedData->m_tabSize; }
 
     RespectImageOrientationEnum respectImageOrientation() const { return static_cast<RespectImageOrientationEnum>(rareInheritedData->m_respectImageOrientation); }
@@ -1440,6 +1443,9 @@ public:
     void setFilter(const FilterOperations& ops) { SET_NESTED_VAR(rareNonInheritedData, m_filter, m_operations, ops); }
     void setBackdropFilter(const FilterOperations& ops) { SET_NESTED_VAR(rareNonInheritedData, m_backdropFilter, m_operations, ops); }
 
+    void setSnapHeightPosition(uint8_t position) { SET_VAR(rareInheritedData, m_snapHeightPosition, position); }
+    void setSnapHeightUnit(uint8_t unit) { SET_VAR(rareInheritedData, m_snapHeightUnit, unit); }
+
     void setTabSize(TabSize size) { SET_VAR(rareInheritedData, m_tabSize, size); }
 
     void setRespectImageOrientation(RespectImageOrientationEnum v) { SET_VAR(rareInheritedData, m_respectImageOrientation, v); }

third_party/WebKit/Source/core/style/StyleRareInheritedData.cpp

@@ -51,6 +51,7 @@ struct SameSizeAsStyleRareInheritedData : public RefCounted<SameSizeAsStyleRareI
     unsigned m_bitfields[2];
     short pagedMediaShorts[2];
     short hyphenationShorts[3];
+    uint8_t snapHeight;
 
     Color touchColors;
     TabSize tabSize;
@@ -96,9 +97,11 @@ StyleRareInheritedData::StyleRareInheritedData()
     , m_subtreeWillChangeContents(false)
     , m_selfOrAncestorHasDirAutoAttribute(false)
     , m_respectImageOrientation(false)
+    , m_snapHeightPosition(0)
     , hyphenationLimitBefore(-1)
     , hyphenationLimitAfter(-1)
     , hyphenationLimitLines(-1)
+    , m_snapHeightUnit(0)
     , tapHighlightColor(ComputedStyle::initialTapHighlightColor())
     , m_tabSize(ComputedStyle::initialTabSize())
 {
@@ -151,10 +154,12 @@ StyleRareInheritedData::StyleRareInheritedData(const StyleRareInheritedData& o)
     , m_subtreeWillChangeContents(o.m_subtreeWillChangeContents)
     , m_selfOrAncestorHasDirAutoAttribute(o.m_selfOrAncestorHasDirAutoAttribute)
     , m_respectImageOrientation(o.m_respectImageOrientation)
+    , m_snapHeightPosition(o.m_snapHeightPosition)
     , hyphenationString(o.hyphenationString)
     , hyphenationLimitBefore(o.hyphenationLimitBefore)
     , hyphenationLimitAfter(o.hyphenationLimitAfter)
     , hyphenationLimitLines(o.hyphenationLimitLines)
+    , m_snapHeightUnit(o.m_snapHeightUnit)
     , textEmphasisCustomMark(o.textEmphasisCustomMark)
     , tapHighlightColor(o.tapHighlightColor)
     , appliedTextDecorations(o.appliedTextDecorations)
@@ -214,7 +219,9 @@ bool StyleRareInheritedData::operator==(const StyleRareInheritedData& o) const
         && m_subtreeWillChangeContents == o.m_subtreeWillChangeContents
         && m_selfOrAncestorHasDirAutoAttribute == o.m_selfOrAncestorHasDirAutoAttribute
         && m_respectImageOrientation == o.m_respectImageOrientation
+        && m_snapHeightPosition == o.m_snapHeightPosition
         && hyphenationString == o.hyphenationString
+        && m_snapHeightUnit == o.m_snapHeightUnit
         && textEmphasisCustomMark == o.textEmphasisCustomMark
         && quotesDataEquivalent(o)
         && m_tabSize == o.m_tabSize

third_party/WebKit/Source/core/style/StyleRareInheritedData.h

@@ -145,11 +145,15 @@ public:
 
     unsigned m_respectImageOrientation : 1;
 
+    unsigned m_snapHeightPosition : 7;
+
     AtomicString hyphenationString;
     short hyphenationLimitBefore;
     short hyphenationLimitAfter;
     short hyphenationLimitLines;
 
+    uint8_t m_snapHeightUnit;
+
     AtomicString textEmphasisCustomMark;
     RefPtr<QuotesData> quotes;