Information from the Oracle v. Google lawsuit includes these bullet points from an internal Google presentation:
Do not develop in the open. Instead, make source code available
after innovation is complete
Lead device concept: Give early access to the software to
partners who build and distribute devices to our specification
(ie [sic], Motorola and Verizon). They get a non-contractual time to
market advantage and in return they align to our standard.
★ Wednesday, 7 September 2011