[Runtime] Re-enable seccomp-bpf sandbox on Linux
[Runtime] Re-enable seccomp-bpf sandbox on Linux

Chromium for Linux has 2 sandboxes: setuid that creates a chroot like
sandbox and thus requires a setuid helper binary that we don't ship, and the
seccomp-bpf sandbox that was previously disabled for no reason.

I'm enabling the seccomp-bpf sandbox back.

tedshroyer/crosswalk,darktears/crosswalk,zliang7/crosswalk,baleboy/crosswalk,RafuCater/crosswalk,minggangw/crosswalk,amaniak/crosswalk,myroot/crosswalk,heke123/crosswalk,chinakids/crosswalk,myroot/crosswalk,TheDirtyCalvinist/spacewalk,DonnaWuDongxia/crosswalk,chuan9/crosswalk,kurli/crosswalk,axinging/crosswalk,stonegithubs/crosswalk,seanlong/crosswalk,hgl888/crosswalk,chinakids/crosswalk,Pluto-tv/crosswalk,TheDirtyCalvinist/spacewalk,pk-sam/crosswalk,darktears/crosswalk,siovene/crosswalk,axinging/crosswalk,darktears/crosswalk,xzhan96/crosswalk,zeropool/crosswalk,lincsoon/crosswalk,jondong/crosswalk,crosswalk-project/crosswalk,pk-sam/crosswalk,TheDirtyCalvinist/spacewalk,heke123/crosswalk,chuan9/crosswalk,zeropool/crosswalk,Pluto-tv/crosswalk,crosswalk-project/crosswalk,weiyirong/crosswalk-1,jondwillis/crosswalk,mrunalk/crosswalk,jondong/crosswalk,pk-sam/crosswalk,RafuCater/crosswalk,qjia7/crosswalk,PeterWangIntel/crosswalk,dreamsxin/crosswalk,XiaosongWei/crosswalk,tedshroyer/crosswalk,lincsoon/crosswalk,huningxin/crosswalk,siovene/crosswalk,Pluto-tv/crosswalk,TheDirtyCalvinist/spacewalk,DonnaWuDongxia/crosswalk,lincsoon/crosswalk,PeterWangIntel/crosswalk,hgl888/crosswalk-efl,hgl888/crosswalk-efl,stonegithubs/crosswalk,stonegithubs/crosswalk,PeterWangIntel/crosswalk,zeropool/crosswalk,bestwpw/crosswalk,hgl888/crosswalk,RafuCater/crosswalk,dreamsxin/crosswalk,heke123/crosswalk,chuan9/crosswalk,alex-zhang/crosswalk,shaochangbin/crosswalk,leonhsl/crosswalk,ZhengXinCN/crosswalk,tomatell/crosswalk,xzhan96/crosswalk,siovene/crosswalk,jpike88/crosswalk,tedshroyer/crosswalk,amaniak/crosswalk,myroot/crosswalk,leonhsl/crosswalk,XiaosongWei/crosswalk,zliang7/crosswalk,DonnaWuDongxia/crosswalk,crosswalk-project/crosswalk,mrunalk/crosswalk,chinakids/crosswalk,chuan9/crosswalk,tomatell/crosswalk,crosswalk-project/crosswalk,marcuspridham/crosswalk,amaniak/crosswalk,amaniak/crosswalk,seanlong/crosswalk,xzhan96/crosswalk,Bysmyyr/crosswalk,axinging/crosswalk,kurli/crosswalk,myroot/crosswalk,wuhengzhi/crosswalk,seanlong/crosswalk,minggangw/crosswalk,dreamsxin/crosswalk,rakuco/crosswalk,chuan9/crosswalk,rakuco/crosswalk,mrunalk/crosswalk,shaochangbin/crosswalk,TheDirtyCalvinist/spacewalk,minggangw/crosswalk,marcuspridham/crosswalk,Bysmyyr/crosswalk,jondong/crosswalk,tedshroyer/crosswalk,tedshroyer/crosswalk,stonegithubs/crosswalk,baleboy/crosswalk,minggangw/crosswalk,chinakids/crosswalk,marcuspridham/crosswalk,wuhengzhi/crosswalk,shaochangbin/crosswalk,ZhengXinCN/crosswalk,qjia7/crosswalk,crosswalk-project/crosswalk-efl,jpike88/crosswalk,marcuspridham/crosswalk,zliang7/crosswalk,minggangw/crosswalk,xzhan96/crosswalk,wuhengzhi/crosswalk,qjia7/crosswalk,jondwillis/crosswalk,jondong/crosswalk,hgl888/crosswalk,huningxin/crosswalk,xzhan96/crosswalk,darktears/crosswalk,dreamsxin/crosswalk,shaochangbin/crosswalk,marcuspridham/crosswalk,XiaosongWei/crosswalk,axinging/crosswalk,seanlong/crosswalk,ZhengXinCN/crosswalk,jondong/crosswalk,XiaosongWei/crosswalk,pk-sam/crosswalk,heke123/crosswalk,xzhan96/crosswalk,leonhsl/crosswalk,PeterWangIntel/crosswalk,zliang7/crosswalk,chuan9/crosswalk,myroot/crosswalk,baleboy/crosswalk,zliang7/crosswalk,weiyirong/crosswalk-1,jpike88/crosswalk,tomatell/crosswalk,qjia7/crosswalk,kurli/crosswalk,mrunalk/crosswalk,ZhengXinCN/crosswalk,crosswalk-project/crosswalk-efl,rakuco/crosswalk,fujunwei/crosswalk,crosswalk-project/crosswalk-efl,qjia7/crosswalk,darktears/crosswalk,bestwpw/crosswalk,rakuco/crosswalk,huningxin/crosswalk,dreamsxin/crosswalk,crosswalk-project/crosswalk-efl,bestwpw/crosswalk,jpike88/crosswalk,kurli/crosswalk,hgl888/crosswalk,stonegithubs/crosswalk,pk-sam/crosswalk,minggangw/crosswalk,baleboy/crosswalk,ZhengXinCN/crosswalk,hgl888/crosswalk,crosswalk-project/crosswalk,Pluto-tv/crosswalk,lincsoon/crosswalk,alex-zhang/crosswalk,RafuCater/crosswalk,fujunwei/crosswalk,ZhengXinCN/crosswalk,baleboy/crosswalk,siovene/crosswalk,pk-sam/crosswalk,weiyirong/crosswalk-1,heke123/crosswalk,jondwillis/crosswalk,jpike88/crosswalk,alex-zhang/crosswalk,crosswalk-project/crosswalk-efl,stonegithubs/crosswalk,weiyirong/crosswalk-1,myroot/crosswalk,wuhengzhi/crosswalk,weiyirong/crosswalk-1,PeterWangIntel/crosswalk,hgl888/crosswalk-efl,zliang7/crosswalk,crosswalk-project/crosswalk-efl,jondong/crosswalk,mrunalk/crosswalk,minggangw/crosswalk,kurli/crosswalk,rakuco/crosswalk,heke123/crosswalk,dreamsxin/crosswalk,chinakids/crosswalk,Bysmyyr/crosswalk,marcuspridham/crosswalk,amaniak/crosswalk,Pluto-tv/crosswalk,RafuCater/crosswalk,alex-zhang/crosswalk,chuan9/crosswalk,shaochangbin/crosswalk,fujunwei/crosswalk,alex-zhang/crosswalk,rakuco/crosswalk,DonnaWuDongxia/crosswalk,jpike88/crosswalk,PeterWangIntel/crosswalk,leonhsl/crosswalk,Pluto-tv/crosswalk,hgl888/crosswalk-efl,heke123/crosswalk,Bysmyyr/crosswalk,axinging/crosswalk,bestwpw/crosswalk,tedshroyer/crosswalk,shaochangbin/crosswalk,kurli/crosswalk,Bysmyyr/crosswalk,lincsoon/crosswalk,tomatell/crosswalk,ZhengXinCN/crosswalk,darktears/crosswalk,marcuspridham/crosswalk,XiaosongWei/crosswalk,tedshroyer/crosswalk,amaniak/crosswalk,xzhan96/crosswalk,jondwillis/crosswalk,crosswalk-project/crosswalk,zliang7/crosswalk,lincsoon/crosswalk,Pluto-tv/crosswalk,jondwillis/crosswalk,lincsoon/crosswalk,hgl888/crosswalk,baleboy/crosswalk,zeropool/crosswalk,chinakids/crosswalk,darktears/crosswalk,zliang7/crosswalk,tomatell/crosswalk,PeterWangIntel/crosswalk,jpike88/crosswalk,dreamsxin/crosswalk,stonegithubs/crosswalk,pk-sam/crosswalk,fujunwei/crosswalk,minggangw/crosswalk,zeropool/crosswalk,hgl888/crosswalk-efl,XiaosongWei/crosswalk,jondong/crosswalk,zeropool/crosswalk,lincsoon/crosswalk,tomatell/crosswalk,huningxin/crosswalk,mrunalk/crosswalk,baleboy/crosswalk,alex-zhang/crosswalk,Bysmyyr/crosswalk,marcuspridham/crosswalk,rakuco/crosswalk,hgl888/crosswalk-efl,jondwillis/crosswalk,fujunwei/crosswalk,baleboy/crosswalk,bestwpw/crosswalk,weiyirong/crosswalk-1,xzhan96/crosswalk,fujunwei/crosswalk,jondwillis/crosswalk,leonhsl/crosswalk,heke123/crosswalk,alex-zhang/crosswalk,DonnaWuDongxia/crosswalk,wuhengzhi/crosswalk,Bysmyyr/crosswalk,crosswalk-project/crosswalk,hgl888/crosswalk,XiaosongWei/crosswalk,weiyirong/crosswalk-1,leonhsl/crosswalk,bestwpw/crosswalk,TheDirtyCalvinist/spacewalk,tomatell/crosswalk,hgl888/crosswalk-efl,hgl888/crosswalk,wuhengzhi/crosswalk,seanlong/crosswalk,DonnaWuDongxia/crosswalk,crosswalk-project/crosswalk-efl,huningxin/crosswalk,axinging/crosswalk,zeropool/crosswalk,leonhsl/crosswalk,jondong/crosswalk,bestwpw/crosswalk,siovene/crosswalk,fujunwei/crosswalk,darktears/crosswalk,axinging/crosswalk,qjia7/crosswalk,siovene/crosswalk,rakuco/crosswalk,seanlong/crosswalk,DonnaWuDongxia/crosswalk,Bysmyyr/crosswalk,huningxin/crosswalk,RafuCater/crosswalk,siovene/crosswalk,amaniak/crosswalk,RafuCater/crosswalk,crosswalk-project/crosswalk