How to update Google chrome in Ubuntu?

First download and install the key from Google Linux Repository. Or run the following commands in the terminal, type the password for the user when prompted.

wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
sudo sh -c 'echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google-chrome.list'
sudo apt-get update

To install:

sudo apt-get install google-chrome-beta

To update only:

sudo apt-get --only-upgrade install google-chrome-stable

Then update (if available) the Network Security Service libraries (libnss), or Chrome will behave weird

sudo apt-get install libnss3-1d

In Ubuntu 18.04 or later libnss3-1d - Network Security Service libraries - transitional package is depreciated and incorporated in generic libnss3 library. (Thanks Bishoy Melek)

sudo apt-get install libnss3

Now you have to kill all instances (may be hidden) of old Google Chrome.

sudo pkill -15 google-chrome
sudo pkill -15 chrome

Then start google-chrome as you start it.

From the Chrome EULA page:

Note: Installing Google Chrome will add the Google repository so your system will automatically keep Google Chrome up to date. If you don't want Google's repository, do "sudo touch /etc/default/google-chrome" before installing the package.

[emphasis theirs]

So, as mgpyone indicated Ubuntu's update-manager should take care of that for you.

Here are the contents of my /etc/apt/sources.list.d/google-chrome.list

deb http://dl.google.com/linux/deb/ stable main

If it does not update properly, just download the last .deb file from: https://www.google.com/chrome/browser/desktop/

The deb file like google-chrome-stable_current_amd64.deb

Then you can:

sudo dpkg -i /path/to/google-chrome-stable_current_amd64.deb

Replace /path/to with your proper path.

It just worked for me on Ubuntu 14.04