What is a "voice-driven" web app? It's a web app that can activate the microphone and turn the user's speech into text that it can process. That text can either be displayed to the user or interpreted as commands. That means controlling the web with nothing but your voice!...
Connect their web app to a cloud platform that provides speech recognition services. For example: Speechly, AWS Transcribe, Azure Cognitive Services...
Google own a speech recognition platform (Google Cloud Speech-to-Text API) and are able to bake a client for this API into Chrome