Google is currently testing “Voice Assistant Search” in Chrome Canary on Android, which when enabled, Chrome browser to use Google Assistant for Voice Search instead of Android’s built-in voice search function.
The chromium team has added the Assistant Voice Search feature flag for now and is planning to enable the functionality in the follow-up CL.

You can enable the feature right away in the latest Chrome Canary. For that, visit chrome://flags, search for “Assitant” and for the “Omnibox Assitant Voice Search” flag, select enabled and relaunch the browser. The voice search popup which you get when you tap on the Microphone icon in Chrome Omnibox may change than the one which you’re seeing at the moment.
Currently, the experimental feature available in Canary provides the following description:
“When enabled, use assistant for Omnibox voice query recognition instead of Android’s built-in voice recognition service. Only works on Android”
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