Harden column splitting code against bad casts.
Harden column splitting code against bad casts.

Make sure that |curr| is a descendant of |fromBlock|. We need to check in every iteration of the loop because moveChildrenTo could have moved |curr|. This is a mitigation and not really a fix against a class of tree craziness.

BUG=189089
TEST=none since current fuzzed testcase does not minimize

Review URL: https://codereview.chromium.org/13852041

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148760 bbb929c8-8fbe-4397-9dbb-9b2b20218538

hgl888/blink-crosswalk-efl,kurli/blink-crosswalk,smishenk/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,hgl888/blink-crosswalk-efl,ondra-novak/blink,Pluto-tv/blink-crosswalk,modulexcite/blink,Pluto-tv/blink-crosswalk,PeterWangIntel/blink-crosswalk,ondra-novak/blink,Bysmyyr/blink-crosswalk,kurli/blink-crosswalk,nwjs/blink,XiaosongWei/blink-crosswalk,XiaosongWei/blink-crosswalk,smishenk/blink-crosswalk,PeterWangIntel/blink-crosswalk,ondra-novak/blink,jtg-gg/blink,Bysmyyr/blink-crosswalk,ondra-novak/blink,nwjs/blink,jtg-gg/blink,crosswalk-project/blink-crosswalk-efl,crosswalk-project/blink-crosswalk-efl,ondra-novak/blink,modulexcite/blink,Bysmyyr/blink-crosswalk,nwjs/blink,XiaosongWei/blink-crosswalk,hgl888/blink-crosswalk-efl,smishenk/blink-crosswalk,kurli/blink-crosswalk,PeterWangIntel/blink-crosswalk,modulexcite/blink,Pluto-tv/blink-crosswalk,ondra-novak/blink,modulexcite/blink,XiaosongWei/blink-crosswalk,smishenk/blink-crosswalk,kurli/blink-crosswalk,smishenk/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,crosswalk-project/blink-crosswalk-efl,kurli/blink-crosswalk,ondra-novak/blink,modulexcite/blink,modulexcite/blink,nwjs/blink,Bysmyyr/blink-crosswalk,Pluto-tv/blink-crosswalk,jtg-gg/blink,jtg-gg/blink,modulexcite/blink,Pluto-tv/blink-crosswalk,XiaosongWei/blink-crosswalk,nwjs/blink,nwjs/blink,XiaosongWei/blink-crosswalk,PeterWangIntel/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,Bysmyyr/blink-crosswalk,Pluto-tv/blink-crosswalk,nwjs/blink,ondra-novak/blink,hgl888/blink-crosswalk-efl,kurli/blink-crosswalk,XiaosongWei/blink-crosswalk,smishenk/blink-crosswalk,smishenk/blink-crosswalk,kurli/blink-crosswalk,hgl888/blink-crosswalk-efl,kurli/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,crosswalk-project/blink-crosswalk-efl,PeterWangIntel/blink-crosswalk,Pluto-tv/blink-crosswalk,smishenk/blink-crosswalk,crosswalk-project/blink-crosswalk-efl,nwjs/blink,XiaosongWei/blink-crosswalk,XiaosongWei/blink-crosswalk,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,modulexcite/blink,ondra-novak/blink,crosswalk-project/blink-crosswalk-efl,jtg-gg/blink,PeterWangIntel/blink-crosswalk,Bysmyyr/blink-crosswalk,PeterWangIntel/blink-crosswalk,modulexcite/blink,kurli/blink-crosswalk,hgl888/blink-crosswalk-efl,PeterWangIntel/blink-crosswalk,hgl888/blink-crosswalk-efl,smishenk/blink-crosswalk,jtg-gg/blink,PeterWangIntel/blink-crosswalk,hgl888/blink-crosswalk-efl,jtg-gg/blink,nwjs/blink,kurli/blink-crosswalk,Bysmyyr/blink-crosswalk,Bysmyyr/blink-crosswalk,Pluto-tv/blink-crosswalk,Bysmyyr/blink-crosswalk,hgl888/blink-crosswalk-efl,nwjs/blink,jtg-gg/blink,jtg-gg/blink,PeterWangIntel/blink-crosswalk,jtg-gg/blink,modulexcite/blink,XiaosongWei/blink-crosswalk,hgl888/blink-crosswalk-efl