This was announced just today on the 1st September 2015. Google launches a new logo, for the new generation.
Please find below a snippet from the announcement:
” Today we’re introducing a new logo and identity family that reflects this reality and shows you when the Google magic is working for you, even on the tiniest screens. As you’ll see, we’ve taken the Google logo and branding, which were originally built for a single desktop browser page, and updated them for a world of seamless computing across an endless number of devices and different kinds of inputs (such as tap, type and talk).”
The team at Ignite Search congratulates Google on this new branding direction and we look forward to continuous improvement of the Google eco-system!
Find out more on http://googleblog.blogspot.com.au/2015/09/google-update.html