Reland: Don't early out recursion into PaintLayerChildren when computing composited bounds.

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 410 matching lines @@
   LayoutRect physicalBoundingBox(const PaintLayer* ancestorLayer) const;
   LayoutRect physicalBoundingBoxIncludingStackingChildren(
       const LayoutPoint& offsetFromRoot,
       CalculateBoundsOptions = MaybeIncludeTransformForAncestorLayer) const;
   LayoutRect fragmentsBoundingBox(const PaintLayer* ancestorLayer) const;
 
   FloatRect boxForFilterOrMask() const;
   LayoutRect boxForClipPath() const;
 
   LayoutRect boundingBoxForCompositingOverlapTest() const;
+  LayoutRect boundingBoxForCompositing() 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; }
 
   void setStaticInlinePosition(LayoutUnit position) {
     m_staticInlinePosition = position;
   }
   void setStaticBlockPosition(LayoutUnit position) {
     m_staticBlockPosition = position;
   }
@@ skipping 653 matching lines @@
         layer.m_needsPaintPhaseDescendantOutlines;
     m_needsPaintPhaseFloat |= layer.m_needsPaintPhaseFloat;
     m_needsPaintPhaseDescendantBlockBackgrounds |=
         layer.m_needsPaintPhaseDescendantBlockBackgrounds;
   }
 
   bool isSelfPaintingLayerForIntrinsicOrScrollingReasons() const;
 
   bool shouldFragmentCompositedBounds(const PaintLayer* compositingLayer) const;
 
+  void expandRectForStackingChildren(const PaintLayer* compositedLayer,
+                                     LayoutRect& result,
+                                     PaintLayer::CalculateBoundsOptions) const;
+
+  // The return value is in the space of |stackingParent|, if non-null, or
+  // |this| otherwise.
+  LayoutRect boundingBoxForCompositingInternal(
+      const PaintLayer* compositedLayer,
+      const PaintLayer* stackingParent,
+      CalculateBoundsOptions) const;
+
   // Self-painting layer is an optimization where we avoid the heavy Layer
   // painting machinery for a Layer allocated only to handle the overflow clip
   // case.
   // FIXME(crbug.com/332791): Self-painting layer should be merged into the
   // overflow-only concept.
   unsigned m_isSelfPaintingLayer : 1;
 
   // If have no self-painting descendants, we don't have to walk our children
   // during painting. This can lead to significant savings, especially if the
   // tree has lots of non-self-painting layers grouped together (e.g. table
@@ skipping 102 matching lines @@
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 CORE_EXPORT void showLayerTree(const blink::PaintLayer*);
 CORE_EXPORT void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif  // Layer_h