The two tech companies have cooperated in the development of Noto Sans, a free font family which is designed to provide a richer and more beautiful reading experience for Japanese, Chinese (both traditional and simplified), and Korean across both apps and OSes.
The Noto Sans font family, or Source Han Sans as Adobe is going to call it, includes over 65,000 glyphs in 7 weights (from light to bold). Its development drew on Adobe's strong design and technical prowess in this area and proven in-country type design experience while Google provided in-country testing resources and expertise, and provided funding that made this project possible.
According to Google:
Noto Sans CJK is a sans serif typeface designed as an intermediate style between the modern and traditional. It is intended to be a multi-purpose digital font for user interface designs, digital content, reading on laptops, mobile devices, and electronic books. Noto Sans CJK is provided in seven weights: Thin, Light, DemiLight, Regular, Medium, Bold, and Black.
Fully supporting CJK requires tens of thousands of characters—these languages share the majority of ideographic characters, but there are also characters that are unique to only one language or to a subset of the languages. One of the primary design goals of Noto Sans CJK is that each script should retain its own distinctive look, which follows regional conventions, while remaining harmonious with the others.
The font family is available with a free subscription to Adobe, but it is probably easier to download it from the the Noto homepage, where you can get the font family in a single file or in a language specific file. You might want to bookmark this page; it's where Google maintains the font families which they give away.