Fix clip-path reference box/coordinate space setup for hit-testing

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 355 matching lines @@
         NeverIncludeTransformForAncestorLayer,
         IncludeTransformsAndCompositedChildLayers,
     };
 
     // 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, CalculateBoundsOptions = MaybeIncludeTransformForAncestorLayer) const;
     LayoutRect fragmentsBoundingBox(const PaintLayer* ancestorLayer) const;
 
+    LayoutRect computeReferenceBox() const;

[Stephen Chennney, 2016/08/26 14:19:28]

I think this should be named boxForReferenceHitTesting or something like that.
boxForReferenceClipsAndMasks?

[fs, 2016/08/26 14:41:51]

We use it when painting too, so I'd go with something more like the latter -
maybe referenceBoxForClipPaths? (Having 'box' as a prefix makes it difficult to
"land" well and still get 'reference' in there - boxForClipPath would be an
alternative I guess.)

+
     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;
     LayoutRect boundingBoxForCompositing(const PaintLayer* ancestorLayer = 0, CalculateBoundsOptions = MaybeIncludeTransformForAncestorLayer) const;
 
     LayoutUnit staticInlinePosition() const { return m_staticInlinePosition; }
     LayoutUnit staticBlockPosition() const { return m_staticBlockPosition; }
 
@@ skipping 513 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