Fix the reference box computation for CSS filter effects.

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

Index: third_party/WebKit/Source/core/paint/PaintLayer.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayer.h b/third_party/WebKit/Source/core/paint/PaintLayer.h
index 4b47a60f6b8c037eafdd3e9489a0d3542a69666c..de287854df4c66a92786de7a264c1a7f82a1f889 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayer.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayer.h
@@ -418,15 +418,12 @@ public:
     bool containsDirtyOverlayScrollbars() const { return m_containsDirtyOverlayScrollbars; }
     void setContainsDirtyOverlayScrollbars(bool dirtyScrollbars) { m_containsDirtyOverlayScrollbars = dirtyScrollbars; }
 
-    FilterOperations computeFilterOperations(const ComputedStyle&);
-    FilterOperations computeBackdropFilterOperations(const ComputedStyle&);
+    FilterOperations computeFilterOperations(const ComputedStyle&) const;
+    FilterOperations computeBackdropFilterOperations(const ComputedStyle&) const;
     bool paintsWithFilters() const;
     bool paintsWithBackdropFilters() const;
-    FilterEffectBuilder* filterEffectBuilder() const
-    {
-        PaintLayerFilterInfo* filterInfo = this->filterInfo();
-        return filterInfo ? filterInfo->builder() : 0;
-    }
+    FilterEffect* lastFilterEffect() const;
+    FilterOutsets filterOutsets() const;
 
     PaintLayerFilterInfo* filterInfo() const { return hasFilterInfo() ? PaintLayerFilterInfo::filterInfoForLayer(this) : 0; }
     PaintLayerFilterInfo* ensureFilterInfo() { return PaintLayerFilterInfo::createFilterInfoForLayerIfNeeded(this); }
@@ -669,6 +666,7 @@ private:
     void updateStackingNode();
 
     void updateReflectionInfo(const ComputedStyle*);
+    FilterEffectBuilder* updateFilterEffectBuilder() const;
 
     // FIXME: We could lazily allocate our ScrollableArea based on style properties ('overflow', ...)
     // but for now, we are always allocating it for LayoutBox as it's safer. crbug.com/467721.