getClientRects() shouldn't clip against any ancestors.

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

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 121 matching lines @@
   LayoutRect boundingRectInFlowThread(offsetFromFlowThread,
                                       descendant.frameRect().size());
   // Set up a fragments relative to the descendant, in the flow thread
   // coordinate space, and convert each of them, individually, to absolute
   // coordinates.
   for (FragmentainerIterator iterator(*this, boundingRectInFlowThread);
        !iterator.atEnd(); iterator.advance()) {
     LayoutRect fragment = boundingRectInFlowThread;
     // We use inclusiveIntersect() because intersect() would reset the
     // coordinates for zero-height objects.
-    fragment.inclusiveIntersect(iterator.fragmentainerInFlowThread());
+    LayoutRect clipRect = iterator.clipRectInFlowThread(
+        MultiColumnFragmentainerGroup::BlockDirectionAxis);
+    fragment.inclusiveIntersect(clipRect);
     fragment.moveBy(-offsetFromFlowThread);
     quads.push_back(descendant.localToAbsoluteQuad(FloatRect(fragment), mode));
   }
 }
 
 bool LayoutFlowThread::nodeAtPoint(HitTestResult& result,
                                    const HitTestLocation& locationInContainer,
                                    const LayoutPoint& accumulatedOffset,
                                    HitTestAction hitTestAction) {
   if (hitTestAction == HitTestBlockBackground)
@@ skipping 79 matching lines @@
 
 void LayoutFlowThread::MultiColumnSetSearchAdapter::collectIfNeeded(
     const MultiColumnSetInterval& interval) {
   if (m_result)
     return;
   if (interval.low() <= m_offset && interval.high() > m_offset)
     m_result = interval.data();
 }
 
 }  // namespace blink