This is a Google feature, and not exclusive to Chrome. But since Chrome Omnibox has Google search built-in, this feature is a bit sweeter on Chrome.
Let us try this now. Type in Set timer for 10 seconds in your omnibox.
You will see Google search setting a timer for 10 seconds, with a nice animation. It also has the count down, and Stop and Reset icons. By default the alarm is on. You can turn it off by clicking the speaker icon below the timer.
If you close the browser tab, the timer will stop. However, Google has done something to help you in case you accidentally close the tab. You will get a confirmation popup letting you know that closing the tab will stop the timer.
Here is a similar tip: Type mailto: on Chrome Omnibox To Open Email Compose Window, Gmail or Outlook
A great tip indeed! Thanks Lifehacker.