Texas Instruments, and
It is likely that Acer, ASUS, HP, Lenovo and Toshiba are looking to produce netbooks and other computers for the proposed OS, while Freescale, Qualcomm and TI are probably involved in the design of semiconductors and other components for those systems.
Adobe is an important member of 'Team Chrome OS' - the absence of Flash and related software could be a handicap for the new platform. (Mind you, it didn't stop the iPhone from becoming one of the most popular smartphones.)
While Google's view of standards-based web-based applications is somewhat at odds with Adobe's, Flash and AIR support would make Chrome OS more attractive, especially for non-corporate users.
Microsoft's Silverlight occupies a similar space, but development of a Linux-compatible implementation has been left to the Novell-sponsored Mono project. The resulting software - Moonlight - has proved controversial.
The list of partners is not comprehensive, so it is interesting to speculate which other companies may be involved. If HP, Lenovo, Toshiba, Acer and ASUS sell Chrome OS netbooks (or even desktops), it's hard to imagine that Dell wouldn't at least offer it as an option.
In their blog post, Pichai and Upson re-emphasised that Google Chrome OS will be an open-source project available at no cost.