Chrome 25 Beta was announced today via the Google Chrome blog. " Using your voice to search on your computer or phone is handy, but there’s so much more you can do with voice commands. Imagine if you could dictate documents, have a freestyle rap battle, or control game characters with your browser using only your voice. With today’s Chrome Beta release, this future is closer than you think."
The Web Speech API is the major feature of Chrome 25. Among the use-cases for this support include voice web search, a speed command interface, speech translation, speech-enabled email support, in-browser speech driving directions, voice activity detection, and much more. This web API is documented at W3.org.
On the Chromium Blog is also more information about the Chrome/Chromium 25 release.