Implement -webkit-box-reflect as a filter.

third_party/WebKit/Source/core/paint/PaintLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
@@ skipping 346 matching lines @@
     // Bounding box relative to some ancestor layer. Pass offsetFromRoot if known.
     LayoutRect physicalBoundingBox(const LayoutPoint& offsetFromRoot) const;
     LayoutRect physicalBoundingBox(const PaintLayer* ancestorLayer) const;
     LayoutRect physicalBoundingBoxIncludingReflectionAndStackingChildren(const LayoutPoint& offsetFromRoot) const;
     LayoutRect fragmentsBoundingBox(const PaintLayer* ancestorLayer) const;
 
     LayoutRect boundingBoxForCompositingOverlapTest() const;
 
     // If true, this layer's children are included in its bounds for overlap testing.
     // We can't rely on the children's positions if this layer has a filter that could have moved the children's pixels around.
-    bool overlapBoundsIncludeChildren() const { return hasFilter() && layoutObject()->style()->filter().hasFilterThatMovesPixels(); }
+    bool overlapBoundsIncludeChildren() const;
 
     // MaybeIncludeTransformForAncestorLayer means that a transform on |ancestorLayer| may be applied to the bounding box,
     // in particular if paintsWithTransform() is true.
     enum CalculateBoundsOptions {
         MaybeIncludeTransformForAncestorLayer,
         NeverIncludeTransformForAncestorLayer,
     };
     LayoutRect boundingBoxForCompositing(const PaintLayer* ancestorLayer = 0, CalculateBoundsOptions = MaybeIncludeTransformForAncestorLayer) const;
 
     LayoutUnit staticInlinePosition() const { return m_staticInlinePosition; }
@@ skipping 20 matching lines @@
     // Note that this transform does not have the perspective-origin baked in.
     TransformationMatrix perspectiveTransform() const;
     FloatPoint perspectiveOrigin() const;
     bool preserves3D() const { return layoutObject()->style()->transformStyle3D() == TransformStyle3DPreserve3D; }
     bool has3DTransform() const { return m_rareData && m_rareData->transform && !m_rareData->transform->isAffine(); }
 
     // FIXME: reflections should force transform-style to be flat in the style: https://bugs.webkit.org/show_bug.cgi?id=106959
     bool shouldPreserve3D() const { return !layoutObject()->hasReflection() && layoutObject()->style()->transformStyle3D() == TransformStyle3DPreserve3D; }
 
     void filterNeedsPaintInvalidation();
-    bool hasFilter() const { return layoutObject()->hasFilter(); }
+
+    // Returns |true| if any property that renders using filter operations is
+    // used (including, but not limited to, 'filter').
+    bool hasFilterInducingProperty() const { return layoutObject()->hasFilterInducingProperty(); }
 
     void* operator new(size_t);
     // Only safe to call from LayoutBoxModelObject::destroyLayer()
     void operator delete(void*);
 
     CompositingState compositingState() const;
 
     // This returns true if our document is in a phase of its lifestyle during which
     // compositing state may legally be read.
     bool isAllowedToQueryCompositingState() const;
@@ skipping 40 matching lines @@
     bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const;
 
     bool containsDirtyOverlayScrollbars() const { return m_containsDirtyOverlayScrollbars; }
     void setContainsDirtyOverlayScrollbars(bool dirtyScrollbars) { m_containsDirtyOverlayScrollbars = dirtyScrollbars; }
 
     FilterOperations computeFilterOperations(const ComputedStyle&) const;
     FilterOperations computeBackdropFilterOperations(const ComputedStyle&) const;
     bool paintsWithFilters() const;
     bool paintsWithBackdropFilters() const;
     FilterEffect* lastFilterEffect() const;
+    bool hasFilterOutsets() const;
     FilterOutsets filterOutsets() const;
 
     PaintLayerFilterInfo* filterInfo() const { return m_rareData ? m_rareData->filterInfo.get() : nullptr; }
     PaintLayerFilterInfo& ensureFilterInfo();
 
     void updateFilters(const ComputedStyle* oldStyle, const ComputedStyle& newStyle);
 
     Node* enclosingNode() const;
 
     bool isInTopLayer() const;
@@ skipping 380 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::PaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h