Merge 109060 - RenderLayer ClipRect not accounting for transforms

Source/WebCore/rendering/RenderLayer.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 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 3619 matching lines @@
         clipRects.setFixed(true);
     }
     else if (renderer()->style()->position() == RelativePosition)
         clipRects.setPosClipRect(clipRects.overflowClipRect());
     else if (renderer()->style()->position() == AbsolutePosition)
         clipRects.setOverflowClipRect(clipRects.posClipRect());
     
     // Update the clip rects that will be passed to child layers.
     if (renderer()->hasOverflowClip() || renderer()->hasClip()) {
         // This layer establishes a clip of some kind.
+
+        // This offset cannot use convertToLayerCoords, because sometimes our rootLayer may be across
+        // some transformed layer boundary, for example, in the RenderLayerCompositor overlapMap, where
+        // clipRects are needed in view space.
         LayoutPoint offset;
-        convertToLayerCoords(rootLayer, offset);
+        offset = roundedIntPoint(renderer()->localToContainerPoint(FloatPoint(), rootLayer->renderer()));
         RenderView* view = renderer()->view();
         ASSERT(view);
         if (view && clipRects.fixed() && rootLayer->renderer() == view) {
             offset -= view->frameView()->scrollOffsetForFixedPosition();
         }
         
         if (renderer()->hasOverflowClip()) {
             ClipRect newOverflowClip = toRenderBox(renderer())->overflowClipRect(offset, region, relevancy);
             if (renderer()->style()->hasBorderRadius())
                 newOverflowClip.setHasRadius(true);
@@ skipping 848 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif