Steam won't start on Ubuntu 15.10

I just switched from Windows 10 to Ubuntu yesterday (although гve used Ubuntu before). I downloaded Steam and it won't start up. Конечный Trying to run it in the provides this:

asto@asto-desktop:~$ steam
Running Steam on ubuntu 15.10 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Gtk-Message: Failed to load module "unity-gtk-module"
Installing breakpad exception handler for appid(steam)/version(1450127196)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
[1220/001312:ERROR:main_delegate.cc(777)] Could not load cef_extensions.pak
[1220/001312:ERROR:browser_main_loop.cc(203)] Running without the SUID sandbox! See https://code.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
Installing breakpad exception handler for appid(steamwebhelper)/version(20151214111542)
Installing breakpad exception handler for appid(steamwebhelper)/version(1450091742)
[1220/001312:ERROR:main_delegate.cc(777)] Could not load cef_extensions.pak
Installing breakpad exception handler for appid(steamwebhelper)/version(20151214111542)
Installing breakpad exception handler for appid(steamwebhelper)/version(1450127196)
Installing breakpad exception handler for appid(steamwebhelper)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Created shared memory when not owner SteamController_Shared_mem
Wireless receiver firmware /home/asto/.local/share/Steam/ubuntu12_32/../controller_base/d0ggle.bin loaded, version 1442256398.
Installing breakpad exception handler for appid(steam)/version(1450127196)
Installing breakpad exception handler for appid(steam)/version(1450127196)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
assert_20151220001311_1.dmp[8119]: Uploading dump (out-of-process)
/tmp/dumps/assert_20151220001311_1.dmp
/home/asto/.local/share/Steam/steam.sh: linio 756ª:  8060 Adres-eraro             (nekropsio elŝutita) $STEAM_DEBUGGER "$STEAMROOT/$STEAMEXEPATH" "$@"
[1220/001313:WARNING:content_browser_client.cc(622)] No browser info matching frame process id 3 and routing id 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
Refresh rate: 1
assert_20151220001311_1.dmp[8119]: Finished uploading minidump (out-of-process): success = yes
assert_20151220001311_1.dmp[8119]: response: CrashID=bp-7996fe25-58d7-4dcd-acbc-ed5b42151219
assert_20151220001311_1.dmp[8119]: file ''/tmp/dumps/assert_20151220001311_1.dmp'', upload yes: ''CrashID=bp-7996fe25-58d7-4dcd-acbc-ed5b42151219''

I have all of the updates from what I хан tell, and have looked at about fifty posts on this same sort of issue, but none helped. It might be because my OS is Esperante, but I doubt it.