Let mapToVisualRectInAncestorSpace apply ancestor clip if not scrollsOverflow

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1625 matching lines @@
     // For any layout object that doesn't override this method (the main example is LayoutText),
     // the rect is assumed to be in the coordinate space of the object's parent.
 
     if (ancestor == this)
         return true;
 
     if (LayoutObject* parent = this->parent()) {
         if (parent->hasOverflowClip()) {
             LayoutBox* parentBox = toLayoutBox(parent);
             parentBox->mapScrollingContentsRectToBoxSpace(rect);
-            if (parent != ancestor && !parentBox->applyOverflowClip(rect, visualRectFlags))
-                return false;
+            if (parent != ancestor || !parentBox->scrollsOverflow()) {
+                if (!parentBox->applyOverflowClip(rect, visualRectFlags))
+                    return false;
+            }
         }
 
         return parent->mapToVisualRectInAncestorSpace(ancestor, rect, visualRectFlags);
     }
     return true;
 }
 
 void LayoutObject::dirtyLinesFromChangedChild(LayoutObject*)
 {
 }
@@ skipping 2041 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif