If you would like to keep you browser up to date, I think the easiest thing to do is to add the PPA. I will explain how to do this for both Chrome and Chromium. These two browsers are mostly the same, but you can check out the differences here.
Chrome
First you have to install the key. This can be done by opening Terminal and typing
wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
Step two is to add the repository
sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google-chrome.list'
Then you update and, if you haven't already, install Google Chrome
sudo apt-get update
sudo apt-get install google-chrome-stable
Chromium
Chromium is more straight forward. Just add the PPA, update, and install by typing this in Terminal:
sudo add-apt-repository ppa:a-v-shkop/chromium
sudo apt-get update
sudo apt-get install chromium-browser
Looks like your sources file is corrupted and there are broken packages. Remove the corrupted source file by pressing Ctrl + Alt + T to open a terminal, and type in:
sudo rm /etc/apt/sources.list
Then, type in
sudo software-properties-gtk
This will open software-properties-gtk and a new sources.list will be created automatically.
Then change the server to US or to any other server of your choice. You must enable repositories from the new dialog in order to create new sources.list.
Tick all the boxes then click on Revert then click close.
How do I restore the default repositories?
Step 2
Open up a Terminal and type in
sudo apt-get remove --purge google-chrome-stable
Then run
sudo apt-get update && sudo apt-get dist-upgrade -y
Then install Chrome.
Edit
I joined Sunny in a chat to help him fix the problem and deleting /var/lib/dpkg/alternatives/google-chrome by running
sudo rm /var/lib/dpkg/alternatives/google-chrome
and running
sudo apt-get update && sudo apt-get dist-upgrade -y
has fixed the problem and Sunny has said that the errors are not happening any more.
Best Answer
Google Chrome in updated in Ubuntu via normal system update. The Unstable channel is actually the DEV Channel of Google Chrome.
Go to System -> Administration -> Update Manager and update your system and the Google Chrome would be updated to latest DEV release.
Or to selectively upgrade Google Chrome, run this command from the terminal: