I don't follow Android closely, so I don't know how free it is of dependency issues. I do know Android made the news not long ago for not properly submitting the large number of Linux kernel customizations Google makes back upstream for inclusion in the mainline kernel.

Android's custom kernel code is publicly available, mind you. This isn't an issue of GPL violation. Like Nokia with GTK+ though, the further Google allows their fork of the Linux kernel to drift from the mainline, the harder it becomes for them to gain benefits from the improvements happening in the mainline.