Ignore continuations when collapsing an anonymous block.

Source/core/rendering/RenderBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 1104 matching lines @@
     if (child->beingDestroyed())
         return;
     parent->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
     parent->setChildrenInline(child->childrenInline());
     RenderObject* nextSibling = child->nextSibling();
 
     RenderFlowThread* childFlowThread = child->flowThreadContainingBlock();
     CurrentRenderFlowThreadMaintainer flowThreadMaintainer(childFlowThread);
 
     parent->children()->removeChildNode(parent, child, child->hasLayer());
+    // FIXME: Get rid of the temporary disabling of continuations. This is needed by the old
+    // multicol implementation, because of buggy block continuation handling (which is hard and
+    // rather pointless to fix at this point). Support for block continuations can be removed
+    // together with the old multicol implementation. crbug.com/408123
+    RenderBoxModelObject* temporarilyInactiveContinuation = parent->continuation();
+    if (temporarilyInactiveContinuation)
+        parent->setContinuation(0);
     child->moveAllChildrenTo(parent, nextSibling, child->hasLayer());
+    if (temporarilyInactiveContinuation)
+        parent->setContinuation(temporarilyInactiveContinuation);
     // Explicitly delete the child's line box tree, or the special anonymous
     // block handling in willBeDestroyed will cause problems.
     child->deleteLineBoxTree();
     child->destroy();
 }
 
 void RenderBlock::removeChild(RenderObject* oldChild)
 {
     // No need to waste time in merging or removing empty anonymous blocks.
     // We can just bail out if our document is getting destroyed.
@@ skipping 3232 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink