Fix the reference box computation for CSS filter effects.

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 400 matching lines @@
 
     bool paintsWithTransform(GlobalPaintFlags) const;
 
     // Returns true if background phase is painted opaque in the given rect.
     // The query rect is given in local coordinates.
     bool backgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const;
 
     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;
-    }
+    FilterEffectBuilder* filterEffectBuilder() const;

[chrishtr, 2015/11/19 19:12:05]

I think you don't actually need filterEffectBuilder() to be public, just
lastEffect()

[Stephen White, 2015/11/19 19:53:28]

Done.

+    FilterOutsets filterOutsets() const;
 
     PaintLayerFilterInfo* filterInfo() const { return hasFilterInfo() ? PaintLayerFilterInfo::filterInfoForLayer(this) : 0; }
     PaintLayerFilterInfo* ensureFilterInfo() { return PaintLayerFilterInfo::createFilterInfoForLayerIfNeeded(this); }
     void removeFilterInfoIfNeeded()
     {
         if (hasFilterInfo())
             PaintLayerFilterInfo::removeFilterInfoForLayer(this);
     }
 
     bool hasFilterInfo() const { return m_hasFilterInfo; }
@@ skipping 370 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