Use GeometryMapper in PaintLayerClipper.

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 614 matching lines @@
 
   // Compute rects only for this layer
   void computeSelfHitTestRects(LayerHitTestRects&) const;
 
   // FIXME: This should probably return a ScrollableArea but a lot of internal
   // methods are mistakenly exposed.
   PaintLayerScrollableArea* getScrollableArea() const {
     return m_scrollableArea.get();
   }
 
-  PaintLayerClipper clipper() const {
-    return PaintLayerClipper(*this,
-                             RuntimeEnabledFeatures::slimmingPaintV2Enabled());
-  }
+  PaintLayerClipper clipper() const;
 
   bool scrollsOverflow() const;
 
   CompositingReasons potentialCompositingReasonsFromStyle() const {
     return m_rareData ? m_rareData->potentialCompositingReasonsFromStyle
                       : CompositingReasonNone;
   }
   void setPotentialCompositingReasonsFromStyle(CompositingReasons reasons) {
     DCHECK(reasons ==
            (reasons & CompositingReasonComboAllStyleDeterminedReasons));
@@ skipping 596 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