overflow-attachment.patch

diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
index c43a48f..ca14687 100644
--- a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
@@ -2743,6 +2743,11 @@ PassRefPtr<CSSValue> CSSComputedStyleDeclaration::getPropertyCSSValue(CSSPropert
         case CSSPropertyUnicodeRange:
             break;
 
+        // FIXME: Implement these for getComputedStyle.
+        case CSSPropertyWebkitOverflowAttachmentX:
+        case CSSPropertyWebkitOverflowAttachmentY:
+            break;
+
         /* Other unimplemented properties */
         case CSSPropertyPage: // for @page
         case CSSPropertyQuotes: // FIXME: needs implementation
diff --git a/Source/WebCore/css/CSSParser.cpp b/Source/WebCore/css/CSSParser.cpp
index 2098b1e..ff8503d 100644
--- a/Source/WebCore/css/CSSParser.cpp
+++ b/Source/WebCore/css/CSSParser.cpp
@@ -683,6 +683,14 @@ static inline bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, int
         if (valueID == CSSValueVisible || valueID == CSSValueHidden || valueID == CSSValueScroll || valueID == CSSValueAuto || valueID == CSSValueOverlay || valueID == CSSValueWebkitMarquee || valueID == CSSValueWebkitPagedX || valueID == CSSValueWebkitPagedY)
             return true;
         break;
+    case CSSPropertyWebkitOverflowAttachmentX:
+        if (valueID == CSSValueStart || valueID == CSSValueEnd)
+            return true;
+        break;
+    case CSSPropertyWebkitOverflowAttachmentY:
+        if (valueID == CSSValueBefore || valueID == CSSValueAfter)
+            return true;
+        break;
     case CSSPropertyPageBreakAfter: // auto | always | avoid | left | right | inherit
     case CSSPropertyPageBreakBefore:
     case CSSPropertyWebkitColumnBreakAfter:
@@ -1003,6 +1011,8 @@ static inline bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
     case CSSPropertyOverflowY:
+    case CSSPropertyWebkitOverflowAttachmentX:
+    case CSSPropertyWebkitOverflowAttachmentY:
     case CSSPropertyPageBreakAfter:
     case CSSPropertyPageBreakBefore:
     case CSSPropertyPageBreakInside:
diff --git a/Source/WebCore/css/CSSPrimitiveValueMappings.h b/Source/WebCore/css/CSSPrimitiveValueMappings.h
index 532e99c..0653681 100644
--- a/Source/WebCore/css/CSSPrimitiveValueMappings.h
+++ b/Source/WebCore/css/CSSPrimitiveValueMappings.h
@@ -881,6 +881,60 @@ template<> inline CSSPrimitiveValue::operator EBoxSizing() const
     return BORDER_BOX;
 }
 
+template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EOverflowAttachmentX e)
+    : CSSValue(PrimitiveClass)
+{
+    m_primitiveUnitType = CSS_IDENT;
+    switch (e) {
+    case OverflowAttachmentStart:
+        m_value.ident = CSSValueStart;
+        break;
+    case OverflowAttachmentEnd:
+        m_value.ident = CSSValueEnd;
+        break;
+    }
+}
+
+template<> inline CSSPrimitiveValue::operator EOverflowAttachmentX() const
+{
+    switch (m_value.ident) {
+    case CSSValueStart:
+        return OverflowAttachmentStart;
+    case CSSValueEnd:
+        return OverflowAttachmentEnd;
+    }
+
+    ASSERT_NOT_REACHED();
+    return OverflowAttachmentStart;
+}
+
+template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EOverflowAttachmentY e)
+    : CSSValue(PrimitiveClass)
+{
+    m_primitiveUnitType = CSS_IDENT;
+    switch (e) {
+    case OverflowAttachmentBefore:
+        m_value.ident = CSSValueBefore;
+        break;
+    case OverflowAttachmentAfter:
+        m_value.ident = CSSValueAfter;
+        break;
+    }
+}
+
+template<> inline CSSPrimitiveValue::operator EOverflowAttachmentY() const
+{
+    switch (m_value.ident) {
+    case CSSValueBefore:
+        return OverflowAttachmentBefore;
+    case CSSValueAfter:
+        return OverflowAttachmentAfter;
+    }
+
+    ASSERT_NOT_REACHED();
+    return OverflowAttachmentBefore;
+}
+
 template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EBoxDirection e)
     : CSSValue(PrimitiveClass)
 {
diff --git a/Source/WebCore/css/CSSProperty.cpp b/Source/WebCore/css/CSSProperty.cpp
index 3a402cf..0158093 100644
--- a/Source/WebCore/css/CSSProperty.cpp
+++ b/Source/WebCore/css/CSSProperty.cpp
@@ -458,6 +458,8 @@ bool CSSProperty::isInheritedProperty(CSSPropertyID propertyID)
     case CSSPropertyOverflowWrap:
     case CSSPropertyOverflowX:
     case CSSPropertyOverflowY:
+    case CSSPropertyWebkitOverflowAttachmentX:
+    case CSSPropertyWebkitOverflowAttachmentY:
     case CSSPropertyPadding:
     case CSSPropertyPaddingBottom:
     case CSSPropertyPaddingLeft:
diff --git a/Source/WebCore/css/CSSPropertyNames.in b/Source/WebCore/css/CSSPropertyNames.in
index ac3fde5..db39558 100644
--- a/Source/WebCore/css/CSSPropertyNames.in
+++ b/Source/WebCore/css/CSSPropertyNames.in
@@ -349,6 +349,8 @@ z-index
 -webkit-min-logical-height
 -webkit-nbsp-mode
 -webkit-order
+-webkit-overflow-attachment-x
+-webkit-overflow-attachment-y
 -webkit-padding-after
 -webkit-padding-before
 -webkit-padding-end
diff --git a/Source/WebCore/css/StyleBuilder.cpp b/Source/WebCore/css/StyleBuilder.cpp
index 4d878b2..5eb2e1b 100644
--- a/Source/WebCore/css/StyleBuilder.cpp
+++ b/Source/WebCore/css/StyleBuilder.cpp
@@ -1896,6 +1896,8 @@ StyleBuilder::StyleBuilder()
     setPropertyHandler(CSSPropertyOutlineColor, ApplyPropertyColor<NoInheritFromParent, &RenderStyle::outlineColor, &RenderStyle::setOutlineColor, &RenderStyle::setVisitedLinkOutlineColor, &RenderStyle::color>::createHandler());
     setPropertyHandler(CSSPropertyOutlineOffset, ApplyPropertyComputeLength<int, &RenderStyle::outlineOffset, &RenderStyle::setOutlineOffset, &RenderStyle::initialOutlineOffset>::createHandler());
     setPropertyHandler(CSSPropertyOutlineStyle, ApplyPropertyOutlineStyle::createHandler());
+    setPropertyHandler(CSSPropertyWebkitOverflowAttachmentX, ApplyPropertyDefault<EOverflowAttachmentX, &RenderStyle::overflowAttachmentX, EOverflowAttachmentX, &RenderStyle::setOverflowAttachmentX, EOverflowAttachmentX, &RenderStyle::initialOverflowAttachmentX>::createHandler());
+    setPropertyHandler(CSSPropertyWebkitOverflowAttachmentY, ApplyPropertyDefault<EOverflowAttachmentY, &RenderStyle::overflowAttachmentY, EOverflowAttachmentY, &RenderStyle::setOverflowAttachmentY, EOverflowAttachmentY, &RenderStyle::initialOverflowAttachmentY>::createHandler());
     setPropertyHandler(CSSPropertyOutlineWidth, ApplyPropertyComputeLength<unsigned short, &RenderStyle::outlineWidth, &RenderStyle::setOutlineWidth, &RenderStyle::initialOutlineWidth, NormalDisabled, ThicknessEnabled>::createHandler());
     setPropertyHandler(CSSPropertyOverflow, ApplyPropertyExpanding<ExpandValue, CSSPropertyOverflowX, CSSPropertyOverflowY>::createHandler());
     setPropertyHandler(CSSPropertyOverflowWrap, ApplyPropertyDefault<EOverflowWrap, &RenderStyle::overflowWrap, EOverflowWrap, &RenderStyle::setOverflowWrap, EOverflowWrap, &RenderStyle::initialOverflowWrap>::createHandler());
diff --git a/Source/WebCore/rendering/RenderLayer.cpp b/Source/WebCore/rendering/RenderLayer.cpp
index e8d03ea..888dc0a 100644
--- a/Source/WebCore/rendering/RenderLayer.cpp
+++ b/Source/WebCore/rendering/RenderLayer.cpp
@@ -3085,7 +3085,8 @@ void RenderLayer::updateScrollInfoAfterLayout()
         return;
 
     m_scrollDimensionsDirty = true;
-    IntSize originalScrollOffset = scrollOffset();
+    IntPoint originalPosition = IntPoint(scrollOffset());
+    IntPoint originalMaxPosition = maximumScrollPosition();
 
     computeScrollDimensions();
 
@@ -3099,8 +3100,17 @@ void RenderLayer::updateScrollInfoAfterLayout()
 
     updateScrollbarsAfterLayout();
 
-    if (originalScrollOffset != scrollOffset())
-        scrollToOffsetWithoutAnimation(IntPoint(scrollOffset()));
+    IntPoint newPosition = IntPoint(scrollOffset());
+
+    // FIXME: Make this handle vertical writing mode and rtl.
+    // FIXME: We should support a spacing value so being close to the end is the same as touching it.
+    if (box->style()->overflowAttachmentY() == OverflowAttachmentAfter && (!box->everHadLayout() || scrollPosition().y() == originalMaxPosition.y()))
+        newPosition.setY(maximumScrollPosition().y());
+    if (box->style()->overflowAttachmentX() == OverflowAttachmentEnd && (!box->everHadLayout() || scrollPosition().x() == originalMaxPosition.x()))
+        newPosition.setX(maximumScrollPosition().x());
+
+    if (originalPosition != newPosition)
+        scrollToOffsetWithoutAnimation(newPosition);
 
 #if USE(ACCELERATED_COMPOSITING)
     // Composited scrolling may need to be enabled or disabled if the amount of overflow changed.
diff --git a/Source/WebCore/rendering/style/RenderStyle.h b/Source/WebCore/rendering/style/RenderStyle.h
index 02cf0c9..9e37179 100644
--- a/Source/WebCore/rendering/style/RenderStyle.h
+++ b/Source/WebCore/rendering/style/RenderStyle.h
@@ -532,6 +532,9 @@ public:
     EOverflow overflowX() const { return static_cast<EOverflow>(noninherited_flags._overflowX); }
     EOverflow overflowY() const { return static_cast<EOverflow>(noninherited_flags._overflowY); }
 
+    EOverflowAttachmentX overflowAttachmentX() const { return static_cast<EOverflowAttachmentX>(rareNonInheritedData->m_overflowAttachmentX); }
+    EOverflowAttachmentY overflowAttachmentY() const { return static_cast<EOverflowAttachmentY>(rareNonInheritedData->m_overflowAttachmentY); }
+
     EVisibility visibility() const { return static_cast<EVisibility>(inherited_flags._visibility); }
     EVerticalAlign verticalAlign() const { return static_cast<EVerticalAlign>(noninherited_flags._vertical_align); }
     Length verticalAlignLength() const { return m_box->verticalAlign(); }
@@ -1066,6 +1069,9 @@ public:
     void setOutlineStyle(EBorderStyle v) { SET_VAR(m_background, m_outline.m_style, v); }
     void setOutlineColor(const Color& v) { SET_BORDERVALUE_COLOR(m_background, m_outline, v); }
 
+    void setOverflowAttachmentX(EOverflowAttachmentX value) { SET_VAR(rareNonInheritedData, m_overflowAttachmentX, value); }
+    void setOverflowAttachmentY(EOverflowAttachmentY value) { SET_VAR(rareNonInheritedData, m_overflowAttachmentY, value); }
+
     void setOverflowX(EOverflow v) { noninherited_flags._overflowX = v; }
     void setOverflowY(EOverflow v) { noninherited_flags._overflowY = v; }
     void setVisibility(EVisibility v) { inherited_flags._visibility = v; }
@@ -1534,6 +1540,8 @@ public:
     static EListStyleType initialListStyleType() { return Disc; }
     static EOverflow initialOverflowX() { return OVISIBLE; }
     static EOverflow initialOverflowY() { return OVISIBLE; }
+    static EOverflowAttachmentX initialOverflowAttachmentX() { return OverflowAttachmentStart; }
+    static EOverflowAttachmentY initialOverflowAttachmentY() { return OverflowAttachmentBefore; }
     static EPageBreak initialPageBreak() { return PBAUTO; }
     static EPosition initialPosition() { return StaticPosition; }
     static ETableLayout initialTableLayout() { return TAUTO; }
diff --git a/Source/WebCore/rendering/style/RenderStyleConstants.h b/Source/WebCore/rendering/style/RenderStyleConstants.h
index 8c2c0b5..0619f85 100644
--- a/Source/WebCore/rendering/style/RenderStyleConstants.h
+++ b/Source/WebCore/rendering/style/RenderStyleConstants.h
@@ -122,6 +122,14 @@ enum EOverflow {
     OVISIBLE, OHIDDEN, OSCROLL, OAUTO, OOVERLAY, OMARQUEE, OPAGEDX, OPAGEDY
 };
 
+enum EOverflowAttachmentX {
+    OverflowAttachmentStart, OverflowAttachmentEnd
+};
+
+enum EOverflowAttachmentY {
+    OverflowAttachmentBefore, OverflowAttachmentAfter
+};
+
 enum EVerticalAlign {
     BASELINE, MIDDLE, SUB, SUPER, TEXT_TOP,
     TEXT_BOTTOM, TOP, BOTTOM, BASELINE_MIDDLE, LENGTH
diff --git a/Source/WebCore/rendering/style/StyleRareNonInheritedData.cpp b/Source/WebCore/rendering/style/StyleRareNonInheritedData.cpp
index b5a6eff..2557cfc 100644
--- a/Source/WebCore/rendering/style/StyleRareNonInheritedData.cpp
+++ b/Source/WebCore/rendering/style/StyleRareNonInheritedData.cpp
@@ -77,6 +77,8 @@ StyleRareNonInheritedData::StyleRareNonInheritedData()
     , m_appearance(RenderStyle::initialAppearance())
     , m_borderFit(RenderStyle::initialBorderFit())
     , m_textCombine(RenderStyle::initialTextCombine())
+    , m_overflowAttachmentX(OverflowAttachmentStart)
+    , m_overflowAttachmentY(OverflowAttachmentBefore)
 #if ENABLE(CSS3_TEXT)
     , m_textDecorationStyle(RenderStyle::initialTextDecorationStyle())
 #endif // CSS3_TEXT
diff --git a/Source/WebCore/rendering/style/StyleRareNonInheritedData.h b/Source/WebCore/rendering/style/StyleRareNonInheritedData.h
index c4ac0f6..a77c4af 100644
--- a/Source/WebCore/rendering/style/StyleRareNonInheritedData.h
+++ b/Source/WebCore/rendering/style/StyleRareNonInheritedData.h
@@ -179,6 +179,9 @@ public:
     unsigned m_borderFit : 1; // EBorderFit
     unsigned m_textCombine : 1; // CSS3 text-combine properties
 
+    unsigned m_overflowAttachmentX : 1; // EOverflowAttachmentX
+    unsigned m_overflowAttachmentY : 1; // EOverflowAttachmentY
+
 #if ENABLE(CSS3_TEXT)
     unsigned m_textDecorationStyle : 3; // TextDecorationStyle
 #endif // CSS3_TEXT