Merge 118592

Source/WebCore/rendering/RenderObject.cpp

Index: Source/WebCore/rendering/RenderObject.cpp
===================================================================
--- Source/WebCore/rendering/RenderObject.cpp	(revision 118866)
+++ Source/WebCore/rendering/RenderObject.cpp	(working copy)
@@ -592,14 +592,26 @@
 
 static inline bool objectIsRelayoutBoundary(const RenderObject* object)
 {
-    // FIXME: In future it may be possible to broaden this condition in order to improve performance.
-    // Table cells are excluded because even when their CSS height is fixed, their height()
-    // may depend on their contents.
-    return object->isTextControl()
+    // FIXME: In future it may be possible to broaden these conditions in order to improve performance.
+    if (object->isTextControl())
+        return true;
+
 #if ENABLE(SVG)
-        || object->isSVGRoot()
+    if (object->isSVGRoot())
+        return true;
 #endif
-        || (object->hasOverflowClip() && !object->style()->width().isIntrinsicOrAuto() && !object->style()->height().isIntrinsicOrAuto() && !object->style()->height().isPercent() && !object->isTableCell());
+
+    if (!object->hasOverflowClip())
+        return false;
+
+    if (object->style()->width().isIntrinsicOrAuto() || object->style()->height().isIntrinsicOrAuto() || object->style()->height().isPercent())
+        return false;
+
+    // Table parts can't be relayout roots since the table is responsible for layouting all the parts.
+    if (object->isTablePart())
+        return false;
+
+    return true;
 }
 
 void RenderObject::markContainingBlocksForLayout(bool scheduleRelayout, RenderObject* newRoot)