I created a new chromium profile by removing .config/chromium and started the browser.
Visit youtube.com then click anything, no response, and eventually the tab dies.
Attached chrome_debug.log
ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: chromium-browser 31.0.1650.63-0ubuntu0.13.10.1~20131204.1
Uname: Linux 3.12.0-031200-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
Date: Sat Dec 28 22:23:05 2013
Desktop-Session:
DESKTOP_SESSION = ubuntu
XDG_CONFIG_DIRS = /etc/xdg/xdg-ubuntu:/usr/share/upstart/xdg:/etc/xdg
XDG_DATA_DIRS = /usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/
EcryptfsInUse: Yes
Env:
MOZ_PLUGIN_PATH = None
LD_LIBRARY_PATH = None
InstallationDate: Installed on 2012-06-29 (547 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MarkForUpload: True
SourcePackage: chromium-browser
UpgradeStatus: Upgraded to saucy on 2013-07-12 (169 days ago)
chromium-default: CHROMIUM_FLAGS=""
gconf-keys: /desktop/gnome/applications/browser/exec = b'/usr/bin/chromium-browser\n'/desktop/gnome/url-handlers/https/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/https/enabled = b'true\n'/desktop/gnome/url-handlers/http/command = b'/usr/bin/chromium-browser %s\n'/desktop/gnome/url-handlers/http/enabled = b'true\n'/desktop/gnome/session/required_components/windowmanager = b''/apps/metacity/general/compositing_manager = b''/desktop/gnome/interface/icon_theme = b'ubuntu-mono-dark\n'/desktop/gnome/interface/gtk_theme = b'Ambiance\n'
Bah! Started working again.