Simplify computation of the invalidation rect for a frame.

third_party/WebKit/Source/core/paint/PaintLayerClipper.h

Index: third_party/WebKit/Source/core/paint/PaintLayerClipper.h
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerClipper.h b/third_party/WebKit/Source/core/paint/PaintLayerClipper.h
index 2092d7f957a56ea5c530ed6784935af1240f0c5f..0c04bea8494efef9c6a4b557d87aa9336d242178 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerClipper.h
+++ b/third_party/WebKit/Source/core/paint/PaintLayerClipper.h
@@ -147,7 +147,7 @@ private:
 // #container and #fixed are siblings in the paint tree but #container does
 // clip #fixed. This is the reason why we compute the painting clip rects during
 // a layout tree walk and cache them for painting.
-class PaintLayerClipper {
+class CORE_EXPORT PaintLayerClipper {
     DISALLOW_NEW();
     WTF_MAKE_NONCOPYABLE(PaintLayerClipper);
 public:
@@ -156,8 +156,6 @@ public:
     void clearClipRectsIncludingDescendants();
     void clearClipRectsIncludingDescendants(ClipRectsCacheSlot);
 
-    LayoutRect childrenClipRect() const; // Returns the foreground clip rect of the layer in the document's coordinate space.
-
     // Returns the background clip rect of the layer in the local coordinate space. Only looks for clips up to the given ancestor.
     LayoutRect localClipRect(const PaintLayer* ancestorLayer) const;
 
@@ -184,8 +182,6 @@ private:
     }
     void getOrCalculateClipRects(const ClipRectsContext&, ClipRects&) const;
 
-    PaintLayer* clippingRootForPainting() const;
-
     ClipRectsCache& cache() const
     {
         if (!m_cache)