Get rid of anonymous table* wrappers when they are no longer needed.

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 0d5279c5aaa1c30e03cd5b8cd70168e6318c9e38..d905112ba5ca62891de0e4d640c25c2288f23a47 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -2807,7 +2807,14 @@ void RenderObject::destroyAndCleanupAnonymousWrappers()
         if (destroyRootParent->isRenderFlowThread() || destroyRootParent->isAnonymousColumnSpanBlock())
             break;
 
-        if (destroyRootParent->slowFirstChild() != this || destroyRootParent->slowLastChild() != this)
+        if (destroyRootParent->slowFirstChild() != destroyRoot || destroyRootParent->slowLastChild() != destroyRoot)
+            break; // Need to keep the anonymous parent, since it won't become empty by the removal of this renderer.
+
+        // If it's an anonymous table* renderer ancestor that's going to become empty, destroy it,
+        // no matter how far up in the ancestry it is. Otherwise, stop when we have walked one level
+        // up. Table* renderers is the only case where we know that it's necessary and safe to walk
+        // further up than one level.
+        if (destroyRoot != this && !destroyRootParent->isTableCell() && !destroyRootParent->isTableRow() && !destroyRootParent->isTableSection() && !destroyRootParent->isTable())

[Julien - ping for review, 2014/09/08 21:28:49]

This seems very artificial to limit this to table and table parts. I agree with
you that they are the only example where we will walk more than a single level
but this may change and thus I don't think we should special-case table.

[mstensho (USE GERRIT), 2014/09/16 13:00:07]

Done.

             break;
     }