In a sense, yes. If Alphabet had gifted the employees $500, the employees would have received such a declaration on the W2 and therefore would have to pay taxes on that $500 gift. Instead, Alphabet gifts the charity, so the employees do not receive such a declaration so they don't have to pay taxes on the gift.
I'm no accountant, but as I understand the tax world, these two are equivalent to all parties:
1. Alphabet gives employees $500... Employee gives charity $500.
2. Alphabet gives charity $500.
What isn't clear to me is how a Chromebook is valued for these transactions. They could be valued at retail... or at COGS... but there's also services that may come along with them, right?