Google does not put any major restriction. Anyone can download the Android source code and develop hardware powered by it. There are some restrictions on devices that can offer their own apps like the Google Android Market. Google of course does not force anyone to customize their Android offerings with skins or whatever. It is the manufacturers who do that to differentiate their devices from other companies. It is stupid of course. I can see companies shipping their laptops with customized wallpapers and stuff like that but no one changes the default UI that Windows has with shit like Stardock or something like that! You do not expect Windows from Toshiba to look any different than Windows from Dell or HP.
freiedns my question was diff, i asked does manufacutres decide to do android stock OS branding seperatly like Samsung did for ICS with launch of galaxy Nexus or google collaborates with manufacture to launch stock OS with GOOGLE branding at back with manufacture logo
I don't understand. Google does not manufacture Nexus devices, it outsources them to some company. Nexus One was made by HTC, S and Galaxy Nexus by Samsung. They contain stock android. Google is responsible for the software and pushing updates. Any other manufacturer is free to create devices with stock android if they want but they wont come under the nexus series.
nexus series is sort of google brand. just like droid is a verizon brand. google nexus one was sold as htc desire in the market with slightly different design. google nexus s was based on the samsung galaxy s. galaxy nexus is the first phone that is purely being promoted by the manufacturer. it is not even called google galaxy nexus... it is generally called galaxy nexus by samsung. considering it contains their galaxy branding. no one knows why google decided to mess around with nexus branding with galaxy nexus. the phone was initially rumored to be called google nexus prime. that turned out to be not very accurate.