Chrome: You no longer have to tap the microphone or use a keyboard shortcut to launch Google's voice search within Chrome. Instead, just as you can on a mobile device, just say "OK Google" to ask Google to look something up, convert things, or perform other tasks.
You'll need to install the Google Voice Search Hotword extension first. According to the Google Operating System blog:
"Chrome will listen for you to say 'Ok Google' and then send the sound of the next thing you say, plus a few seconds before, to Google," informs the options page. By default, Google stops listening after 5 minutes to reduce battery consumption on a laptop.
Hotword detection works offline and doesn't send the recording to Google's servers until you say "OK Google".
This could come in handy when you're hands are full and need some quick info or want Google to set a timer for you.
Google Voice Search Hotword (Beta) [Chrome Web Store]