Correct multicol dirty rect for scrolled and flipped blocks writing mode.

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

Index: third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp b/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
index 3002b95552d8e3b2389fee4d20dee9fd8c2df18d..9e34cd4c419fcf9b595ae84706623bd262009aa2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutFlowThread.cpp
@@ -163,13 +163,10 @@ LayoutUnit LayoutFlowThread::nextLogicalTopForUnbreakableContent(LayoutUnit flow
     return columnSet->nextLogicalTopForUnbreakableContent(flowThreadOffset, contentLogicalHeight);
 }
 
-void LayoutFlowThread::collectLayerFragments(PaintLayerFragments& layerFragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRectInFlowThread)
+void LayoutFlowThread::collectLayerFragments(PaintLayerFragments& layerFragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRectInMulticolContainer)
 {
     ASSERT(!m_columnSetsInvalidated);
 
-    LayoutRect dirtyRectInMulticolContainer(dirtyRectInFlowThread);
-    dirtyRectInMulticolContainer.moveBy(location());
-
     for (LayoutMultiColumnSetList::const_iterator iter = m_multiColumnSetList.begin(); iter != m_multiColumnSetList.end(); ++iter) {
         LayoutMultiColumnSet* columnSet = *iter;
         columnSet->collectLayerFragments(layerFragments, layerBoundingBox, dirtyRectInMulticolContainer);