libcef seems to belong to chromium so it's probably not steam's problem but it may help updating it or reporting it upstream or something.

Steps to reproduce:
Go to the big picture mode browser, search for "html5 scratchpad" or paste http://www.chromeexperiments.com/detail/html5-canvas-scratch-pad/ and click launch.

Backtrace: https://gist.github.com/4434250

So I'm using Archlinux 64 Bit and mesa / xf86-video-intel from git so it could be a fringe issue but it could also indicate a problem somewhere.

Processor Information:
    Vendor:  GenuineIntel
    Speed: 2201 Mhz
    8 logical processors
    4 physical processors
    HyperThreading:  Supported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Unsupported
    SSE41:  Supported
    SSE42:  Supported

Network Information:
    Network Speed:  

Operating System Version:
    "Arch Linux" (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.7.1-2-ARCH
    X Server vendor:  The X.Org Foundation
    X Server release:  11301000

Video Card:
    Driver:  Intel Open Source Technology Center Mesa DRI Intel(R) Ivybridge Mobile x86/MMX/SSE2

    Driver Version:  3.0 Mesa 9.1-devel (git-66ea6e8)
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x1002
    DeviceID:  0x6800
    Number of Monitors:  2
    Number of Logical Video Cards:  2
    Primary Display Resolution:  1920 x 1080
    Desktop Resolution: 3840 x 1080
    Primary Display Size: 23,54" x 13,23"  (26,97" diag)
                                            59,8cm x 33,6cm  (68,5cm diag)
    Primary VRAM Not Detected

Sound card:
    Audio device: Intel PantherPoint HDMI

Memory:
    RAM:  32071 Mb

Miscellaneous:
    UI Language:  English
    LANG:  de_DE.utf8
    Microphone:  Not set
    Total Hard Disk Space Available:  201586 Mb
    Largest Free Hard Disk Block:  11668 Mb

Installed software:

Recent Failure Reports: