I have had almost the exact same problem on a Raspberry Pi 2 running Ubuntu Mate 15.10.
uname -a:
Linux RaspberryPi 3.18.0-20-rpi2 #21-Ubuntu SMP PREEMPT Sun Apr 5 01:56:02 UTC 2015 armv7l armv7l armv7l GNU/Linux
$ chromium-browser
[2815:2815:0403/092234:ERROR:sandbox_linux.cc(334)] InitializeSandbox() called with multiple threads in process gpu-process
Segmentation fault (core dumped)
I have had almost the exact same problem on a Raspberry Pi 2 running Ubuntu Mate 15.10.
uname -a:
Linux RaspberryPi 3.18.0-20-rpi2 #21-Ubuntu SMP PREEMPT Sun Apr 5 01:56:02 UTC 2015 armv7l armv7l armv7l GNU/Linux
$ chromium-browser 0403/092234: ERROR:sandbox_ linux.cc( 334)] InitializeSandbox() called with multiple threads in process gpu-process
[2815:2815:
Segmentation fault (core dumped)