Generalize paint chunks to clips, and implement clips in LayerPainter.

Source/core/paint/LayerPainter.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef LayerPainter_h
 #define LayerPainter_h
 
 #include "core/rendering/LayerFragment.h"
 #include "core/rendering/LayerPaintingInfo.h"
 
 namespace blink {
 
 class ClipRect;
+class PaintClipRecorder;
 struct PaintInfo;
 class LayoutPoint;
 class RenderLayer;
 
 class LayerPainter {
 public:
     LayerPainter(RenderLayer& renderLayer) : m_renderLayer(renderLayer) { }
 
     // The paint() method paints the layers that intersect the damage rect from back to front.
     //  paint() assumes that the caller will clip to the bounds of damageRect if necessary.
@@ skipping 22 matching lines @@
     void paintForegroundForFragmentsWithPhase(PaintPhase, const LayerFragments&, GraphicsContext*, const LayerPaintingInfo&, PaintBehavior, RenderObject* paintingRootForRenderer, PaintLayerFlags);
     void paintOutlineForFragments(const LayerFragments&, GraphicsContext*, const LayerPaintingInfo&, PaintBehavior, RenderObject* paintingRootForRenderer, PaintLayerFlags);
     void paintOverflowControlsForFragments(const LayerFragments&, GraphicsContext*, const LayerPaintingInfo&, PaintLayerFlags);
     void paintMaskForFragments(const LayerFragments&, GraphicsContext*, const LayerPaintingInfo&, RenderObject* paintingRootForRenderer, PaintLayerFlags);
     void paintChildClippingMaskForFragments(const LayerFragments&, GraphicsContext*, const LayerPaintingInfo&, RenderObject* paintingRootForRenderer, PaintLayerFlags);
     void paintTransformedLayerIntoFragments(GraphicsContext*, const LayerPaintingInfo&, PaintLayerFlags);
     void beginTransparencyLayers(GraphicsContext*, const RenderLayer* rootLayer, const LayoutRect& paintDirtyRect, const LayoutSize& subPixelAccumulation, PaintBehavior);
 
     enum BorderRadiusClippingRule { IncludeSelfForBorderRadius, DoNotIncludeSelfForBorderRadius };
 
-    void clipToRect(const LayerPaintingInfo&, GraphicsContext*, const ClipRect&, PaintLayerFlags, BorderRadiusClippingRule = IncludeSelfForBorderRadius);
-    void restoreClip(GraphicsContext*, const LayoutRect& paintDirtyRect, const ClipRect&);
+    void clipToRect(const LayerPaintingInfo&, GraphicsContext*, const ClipRect&, PaintLayerFlags, PaintClipRecorder*, BorderRadiusClippingRule = IncludeSelfForBorderRadius);
+    void restoreClip(GraphicsContext*, const LayoutRect& paintDirtyRect, const ClipRect&, PaintClipRecorder*);
 
     // Returns whether this layer should be painted during sofware painting (i.e., not via calls from CompositedLayerMapping to draw into composited
     // layers).
     bool shouldPaintLayerInSoftwareMode(const LayerPaintingInfo&, PaintLayerFlags paintFlags);
 
     RenderLayer& m_renderLayer;
 };
 
 } // namespace blink
 
 #endif // LayerPainter_h