Remove backface visibility

I made one edit in FrameView while looking at writing
RenderParagraph in Dart and then decided to look for
a slightly larger clean-up to justify committing it.
I found backface-visibility which I removed.

backface-visibility controls painting/hittesting of flipped objects.
https://developer.mozilla.org/en-US/docs/Web/CSS/backface-visibility

It's mostly used as a hack to get layers however. :)

TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/1161623004

engine/core/css/CSSComputedStyleDeclaration.cpp

@@ -179,8 +179,6 @@ static const CSSPropertyID staticComputableProperties[] = {
     CSSPropertyWordWrap,
     CSSPropertyZIndex,
 
-    CSSPropertyBackfaceVisibility,
-    CSSPropertyWebkitBackfaceVisibility,
     CSSPropertyWebkitBackgroundClip,
     CSSPropertyWebkitBackgroundComposite,
     CSSPropertyWebkitBackgroundOrigin,
@@ -1830,9 +1828,6 @@ PassRefPtr<CSSValue> CSSComputedStyleDeclaration::getPropertyCSSValue(CSSPropert
             if (!style->hasAspectRatio())
                 return cssValuePool().createIdentifierValue(CSSValueNone);
             return CSSAspectRatioValue::create(style->aspectRatioNumerator(), style->aspectRatioDenominator());
-        case CSSPropertyBackfaceVisibility:
-        case CSSPropertyWebkitBackfaceVisibility:
-            return cssValuePool().createIdentifierValue((style->backfaceVisibility() == BackfaceVisibilityHidden) ? CSSValueHidden : CSSValueVisible);
         case CSSPropertyWebkitBorderImage:
             return valueForNinePieceImage(style->borderImage(), *style);
         case CSSPropertyBorderImageOutset:

engine/core/css/CSSPrimitiveValueMappings.h

@@ -267,37 +267,6 @@ template<> inline CSSPrimitiveValue::operator CompositeOperator() const
     return CompositeClear;
 }
 
-template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EBackfaceVisibility e)
-    : CSSValue(PrimitiveClass)
-{
-    m_primitiveUnitType = CSS_VALUE_ID;
-    switch (e) {
-    case BackfaceVisibilityVisible:
-        m_value.valueID = CSSValueVisible;
-        break;
-    case BackfaceVisibilityHidden:
-        m_value.valueID = CSSValueHidden;
-        break;
-    }
-}
-
-template<> inline CSSPrimitiveValue::operator EBackfaceVisibility() const
-{
-    ASSERT(isValueID());
-    switch (m_value.valueID) {
-    case CSSValueVisible:
-        return BackfaceVisibilityVisible;
-    case CSSValueHidden:
-        return BackfaceVisibilityHidden;
-    default:
-        break;
-    }
-
-    ASSERT_NOT_REACHED();
-    return BackfaceVisibilityHidden;
-}
-
-
 template<> inline CSSPrimitiveValue::CSSPrimitiveValue(EFillAttachment e)
     : CSSValue(PrimitiveClass)
 {

engine/core/css/CSSProperties.in

@@ -111,7 +111,6 @@ align-items custom_all
 // LAYOUT
 align-self custom_all
 
-backface-visibility
 background-attachment custom_all
 background-clip custom_all
 background-color animatable, custom_all
@@ -311,7 +310,6 @@ animation-timing-function custom_all
 
 filter animatable, custom_value
 -webkit-aspect-ratio inherited, custom_all
--webkit-backface-visibility use_handlers_for=CSSPropertyBackfaceVisibility
 -webkit-background-clip use_handlers_for=CSSPropertyBackgroundClip
 -webkit-background-composite custom_all
 -webkit-background-origin use_handlers_for=CSSPropertyBackgroundOrigin

engine/core/css/parser/BisonCSSParser-in.cpp

@@ -385,9 +385,6 @@ bool isValidKeywordPropertyAndValue(CSSPropertyID propertyId, CSSValueID valueID
     case CSSPropertyTouchActionDelay: // none | script
         ASSERT(RuntimeEnabledFeatures::cssTouchActionDelayEnabled());
         return valueID == CSSValueScript || valueID == CSSValueNone;
-    case CSSPropertyBackfaceVisibility:
-    case CSSPropertyWebkitBackfaceVisibility:
-        return valueID == CSSValueVisible || valueID == CSSValueHidden;
     case CSSPropertyWebkitBoxDecorationBreak:
         return valueID == CSSValueClone || valueID == CSSValueSlice;
     case CSSPropertyAlignContent:
@@ -465,8 +462,6 @@ bool isKeywordPropertyID(CSSPropertyID propertyId)
     case CSSPropertyTextRendering:
     case CSSPropertyTouchActionDelay:
     case CSSPropertyUnicodeBidi:
-    case CSSPropertyBackfaceVisibility:
-    case CSSPropertyWebkitBackfaceVisibility:
     case CSSPropertyWebkitBorderAfterStyle:
     case CSSPropertyWebkitBorderBeforeStyle:
     case CSSPropertyWebkitBorderEndStyle:

engine/core/frame/FrameView.cpp

@@ -316,7 +316,7 @@ void FrameView::layout(bool allowSubtree)
                 m_lastViewportSize = layoutSize();
             }
 
-            m_size = LayoutSize(layoutSize().width(), layoutSize().height());
+            m_size = LayoutSize(layoutSize());
         }
 
         layer = rootForThisLayout->enclosingLayer();

engine/core/rendering/RenderBox.cpp

@@ -637,14 +637,6 @@ bool RenderBox::hitTestLayer(RenderLayer* rootLayer, RenderLayer* containerLayer
     layer()->stackingNode()->updateLayerListsIfNeeded();
     layer()->update3DTransformedDescendantStatus();
 
-    // Check for hit test on backface if backface-visibility is 'hidden'
-    if (localTransformState && style()->backfaceVisibility() == BackfaceVisibilityHidden) {
-        TransformationMatrix invertedMatrix = localTransformState->m_accumulatedTransform.inverse();
-        // If the z-vector of the matrix is negative, the back is facing towards the viewer.
-        if (invertedMatrix.m33() < 0)
-            return 0;
-    }
-
     RefPtr<HitTestingTransformState> unflattenedTransformState = localTransformState;
     if (localTransformState && !style()->preserves3D()) {
         // Keep a copy of the pre-flattening state, for computing z-offsets for the container

engine/core/rendering/RenderBox.h

@@ -74,7 +74,7 @@ public:
     // position:static elements that are not flex-items get their z-index coerced to auto.
     virtual LayerType layerTypeRequired() const
     {
-        if (isPositioned() || createsGroup() || hasClipPath() || hasTransform() || hasHiddenBackface() || !style()->hasAutoZIndex())
+        if (isPositioned() || createsGroup() || hasClipPath() || hasTransform() || !style()->hasAutoZIndex())
             return NormalLayer;
         if (hasOverflowClip())
             return OverflowClipLayer;

engine/core/rendering/RenderObject.cpp

@@ -1875,11 +1875,6 @@ bool RenderObject::nodeAtFloatPoint(const HitTestRequest&, HitTestResult&, const
     return false;
 }
 
-bool RenderObject::isRelayoutBoundaryForInspector() const
-{
-    return objectIsRelayoutBoundary(this);
-}
-
 bool RenderObject::isAllowedToModifyRenderTreeStructure(Document& document)
 {
     return document.lifecycle().stateAllowsRenderTreeMutations();

engine/core/rendering/RenderObject.h

@@ -338,7 +338,6 @@ public:
 
     bool hasTransform() const { return m_bitfields.hasTransform(); }
     bool hasClipPath() const { return style() && style()->clipPath(); }
-    bool hasHiddenBackface() const { return style() && style()->backfaceVisibility() == BackfaceVisibilityHidden; }
 
     inline bool preservesNewline() const;
 
@@ -361,9 +360,6 @@ public:
     // is true if the renderer returned is an ancestor of paintInvalidationContainer.
     RenderObject* container(const RenderBox* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
 
-    // TODO(esprehn): Remove this.
-    RenderObject* hoverAncestor() const { return parent(); }
-
     Element* offsetParent() const;
 
     void markContainingBlocksForLayout(bool scheduleRelayout = true, RenderObject* newRoot = 0, SubtreeLayoutScope* = 0);
@@ -501,6 +497,7 @@ public:
     const RenderView* containerForPaintInvalidation() const;
     const RenderBox* adjustCompositedContainerForSpecialAncestors(const RenderBox* paintInvalidationContainer) const;
 
+    // Overriden by RenderText for character length, used in line layout code.
     virtual unsigned length() const { return 1; }
 
     // FIXME(sky): Remove
@@ -592,8 +589,6 @@ public:
 
     RespectImageOrientationEnum shouldRespectImageOrientation() const;
 
-    bool isRelayoutBoundaryForInspector() const;
-
     bool onlyNeededPositionedMovementLayout() const { return m_bitfields.onlyNeededPositionedMovementLayout(); }
     void setOnlyNeededPositionedMovementLayout(bool b) { m_bitfields.setOnlyNeededPositionedMovementLayout(b); }
 

engine/core/rendering/style/RenderStyle.h

@@ -670,7 +670,6 @@ public:
     ETransformStyle3D transformStyle3D() const { return static_cast<ETransformStyle3D>(rareNonInheritedData->m_transformStyle3D); }
     bool preserves3D() const { return rareNonInheritedData->m_transformStyle3D == TransformStyle3DPreserve3D; }
 
-    EBackfaceVisibility backfaceVisibility() const { return static_cast<EBackfaceVisibility>(rareNonInheritedData->m_backfaceVisibility); }
     float perspective() const { return rareNonInheritedData->m_perspective; }
     bool hasPerspective() const { return rareNonInheritedData->m_perspective > 0; }
     const Length& perspectiveOriginX() const { return rareNonInheritedData->m_perspectiveOriginX; }
@@ -953,7 +952,6 @@ public:
     }
 
     void setTransformStyle3D(ETransformStyle3D b) { SET_VAR(rareNonInheritedData, m_transformStyle3D, b); }
-    void setBackfaceVisibility(EBackfaceVisibility b) { SET_VAR(rareNonInheritedData, m_backfaceVisibility, b); }
     void setPerspective(float p) { SET_VAR(rareNonInheritedData, m_perspective, p); }
     void setPerspectiveOriginX(const Length& l) { SET_VAR(rareNonInheritedData, m_perspectiveOriginX, l); }
     void setPerspectiveOriginY(const Length& l) { SET_VAR(rareNonInheritedData, m_perspectiveOriginY, l); }
@@ -1107,7 +1105,6 @@ public:
     static EPointerEvents initialPointerEvents() { return PE_AUTO; }
     static float initialTransformOriginZ() { return 0; }
     static ETransformStyle3D initialTransformStyle3D() { return TransformStyle3DFlat; }
-    static EBackfaceVisibility initialBackfaceVisibility() { return BackfaceVisibilityVisible; }
     static float initialPerspective() { return 0; }
     static Length initialPerspectiveOriginX() { return Length(50.0, Percent); }
     static Length initialPerspectiveOriginY() { return Length(50.0, Percent); }

engine/core/rendering/style/RenderStyleConstants.h

@@ -204,10 +204,6 @@ enum ETransformStyle3D {
     TransformStyle3DFlat, TransformStyle3DPreserve3D
 };
 
-enum EBackfaceVisibility {
-    BackfaceVisibilityVisible, BackfaceVisibilityHidden
-};
-
 enum Hyphens { HyphensNone, HyphensManual, HyphensAuto };
 
 enum TextEmphasisFill { TextEmphasisFillFilled, TextEmphasisFillOpen };

engine/core/rendering/style/StyleRareNonInheritedData.cpp

@@ -42,7 +42,6 @@ StyleRareNonInheritedData::StyleRareNonInheritedData()
     , m_order(RenderStyle::initialOrder())
     , m_objectPosition(RenderStyle::initialObjectPosition())
     , m_transformStyle3D(RenderStyle::initialTransformStyle3D())
-    , m_backfaceVisibility(RenderStyle::initialBackfaceVisibility())
     , m_alignContent(RenderStyle::initialAlignContent())
     , m_alignItems(RenderStyle::initialAlignItems())
     , m_alignItemsOverflowAlignment(RenderStyle::initialAlignItemsOverflowAlignment())
@@ -85,7 +84,6 @@ StyleRareNonInheritedData::StyleRareNonInheritedData(const StyleRareNonInherited
     , m_order(o.m_order)
     , m_objectPosition(o.m_objectPosition)
     , m_transformStyle3D(o.m_transformStyle3D)
-    , m_backfaceVisibility(o.m_backfaceVisibility)
     , m_alignContent(o.m_alignContent)
     , m_alignItems(o.m_alignItems)
     , m_alignItemsOverflowAlignment(o.m_alignItemsOverflowAlignment)
@@ -132,7 +130,6 @@ bool StyleRareNonInheritedData::operator==(const StyleRareNonInheritedData& o) c
         && m_order == o.m_order
         && m_objectPosition == o.m_objectPosition
         && m_transformStyle3D == o.m_transformStyle3D
-        && m_backfaceVisibility == o.m_backfaceVisibility
         && m_alignContent == o.m_alignContent
         && m_alignItems == o.m_alignItems
         && m_alignItemsOverflowAlignment == o.m_alignItemsOverflowAlignment

engine/core/rendering/style/StyleRareNonInheritedData.h

@@ -100,7 +100,6 @@ public:
     LengthPoint m_objectPosition;
 
     unsigned m_transformStyle3D : 1; // ETransformStyle3D
-    unsigned m_backfaceVisibility : 1; // EBackfaceVisibility
 
     unsigned m_alignContent : 3; // EAlignContent
     unsigned m_alignItems : 4; // ItemPosition

engine/public/platform/WebLayer.h

@@ -94,15 +94,6 @@ public:
     // position rather than their tree order.
     virtual void setRenderingContext(int id) = 0;
 
-    // Mark that this layer should use its parent's transform and double-sided
-    // properties in determining this layer's backface visibility instead of
-    // using its own properties. If this property is set, this layer must
-    // have a parent, and the parent may not have this property set.
-    // Note: This API is to work around issues with visibility the handling of
-    // WebKit layers that have a contents layer (canvas, plugin, WebGL, video,
-    // etc).
-    virtual void setUseParentBackfaceVisibility(bool) = 0;
-
     virtual void setBackgroundColor(WebColor) = 0;
     virtual WebColor backgroundColor() const = 0;