Simplify computation of the invalidation rect for a frame.

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. 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>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 152 matching lines @@
 void PaintLayerClipper::clearClipRectsIncludingDescendants(ClipRectsCacheSlot cacheSlot)
 {
     if (m_cache)
         m_cache->clear(cacheSlot);
 
     for (PaintLayer* layer = m_layoutObject.layer()->firstChild(); layer; layer = layer->nextSibling()) {
         layer->clipper().clearClipRectsIncludingDescendants(cacheSlot);
     }
 }
 
-LayoutRect PaintLayerClipper::childrenClipRect() const
-{
-    // FIXME: border-radius not accounted for.
-    // FIXME: Flow thread based columns not accounted for.
-    PaintLayer* clippingRootLayer = clippingRootForPainting();
-    LayoutRect layerBounds;
-    ClipRect backgroundRect, foregroundRect;
-    // Need to use uncached clip rects, because the value of 'dontClipToOverflow' may be different from the painting path (<rdar://problem/11844909>).
-    ClipRectsContext context(clippingRootLayer, UncachedClipRects);
-    calculateRects(context, LayoutRect(m_layoutObject.view()->unscaledDocumentRect()), layerBounds, backgroundRect, foregroundRect);
-    return LayoutRect(clippingRootLayer->layoutObject()->localToAbsoluteQuad(FloatQuad(FloatRect(foregroundRect.rect()))).enclosingBoundingBox());
-}
 
 LayoutRect PaintLayerClipper::localClipRect(const PaintLayer* clippingRootLayer) const
 {
     LayoutRect layerBounds;
     ClipRect backgroundRect, foregroundRect;
     ClipRectsContext context(clippingRootLayer, PaintingClipRects);
     calculateRects(context, LayoutRect(LayoutRect::infiniteIntRect()), layerBounds, backgroundRect, foregroundRect);
 
     LayoutRect clipRect = backgroundRect.rect();
     // TODO(chrishtr): avoid converting to IntRect and back.
@@ skipping 124 matching lines @@
 }
 
 void PaintLayerClipper::getOrCalculateClipRects(const ClipRectsContext& context, ClipRects& clipRects) const
 {
     if (context.usesCache())
         clipRects = *getClipRects(context);
     else
         calculateClipRects(context, clipRects);
 }
 
-PaintLayer* PaintLayerClipper::clippingRootForPainting() const
-{
-    const PaintLayer* current = m_layoutObject.layer();
-    // FIXME: getting rid of current->hasCompositedLayerMapping() here breaks the
-    // compositing/backing/no-backing-for-clip.html layout test, because there is a
-    // "composited but paints into ancestor" layer involved. However, it doesn't make sense that
-    // that check would be appropriate here but not inside the while loop below.
-    if (current->isPaintInvalidationContainer() || current->hasCompositedLayerMapping())
-        return const_cast<PaintLayer*>(current);
-
-    while (current) {
-        if (current->isRootLayer())
-            return const_cast<PaintLayer*>(current);
-
-        current = current->compositingContainer();
-        ASSERT(current);
-        if (current->transform() || current->isPaintInvalidationContainer())
-            return const_cast<PaintLayer*>(current);
-    }
-
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
 bool PaintLayerClipper::shouldRespectOverflowClip(const ClipRectsContext& context) const
 {
     PaintLayer* layer = m_layoutObject.layer();
     if (layer != context.rootLayer)
         return true;
 
     if (context.respectOverflowClip == IgnoreOverflowClip)
         return false;
 
     if (layer->isRootLayer() && context.respectOverflowClipForViewport == IgnoreOverflowClip)
         return false;
 
     return true;
 }
 
 } // namespace blink