google-chrome-stable is availeble on 3rd Party Repository: Google Chrome (For Stable).
Follow the instruction for installation:
wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
sudo sh -c 'echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google-chrome.list'
sudo apt-get update
sudo apt-get install google-chrome-stable
Click Download and a small window will pop up with some download options.
Select the ".deb" for Ubuntu.
Note:You can only download 64-bit versions for Linux as of at least February 2016
It will give you the option to "Open with..." or "Save File". The default option for "Open with..." is to open via "Software Install". Select this option.
In a few moments ubuntu software center should open up with the .deb file you have downloaded ready to install. (I already have chrome installed) Click the install button and you will be prompted for your password to start the installation.
Note: Chrome will also be updated through the normal Ubuntu update process so you can expect to grab the latest version when Ubuntu updates.