While this new feature was seen sporadically over the last month or so, more Google Search users have recently reported seeing this streamlined way to install new apps on their mobile devices. To see if it is live for you, go to Google Search and type in the name of an app. You will see the results return with an install link for the app. If you click on it and are taken to the Google Play Store, the new feature has yet to hit your device. On the other hand, if tapping on the install link brings up a permissions box, you have the new feature on your handset or slate. Accept the permissions and you will see a mini-version of the Play Store listing with an install button.
If you want to see what this new feature looks like, feel free to click on the slideshow below. Only now has Google started a wider roll out, so if this is not yet working for you, try again in a few days.