I dont think that they will get into bitcoin or altcoin mining, however if someday they starts investing in mining i think they would create their own cryptocurrency and mining their own rather than investing in bitcoin or any altcoins since people will interested on what they've created.
To be honest i really love if those Tech Giants starts accepting bitcoin as payment processor it would make bitcoin gain more popularity as well as the price would be up, also give us an opportunity to spend our coin.