The A350 has "black" windshields: Source
Does anybody know why are the windshields different?
The gold tint on the 787 window is a conductive coating for de-icing.
Dreamliner jet flight-deck crews will view the world through commercial aviation's largest windshields by PPG, kept clear of fog and ice with gold and indium-tin oxide heating systems. source
The A350 also has a windshield anti-ice system. It is referred to in this answer. One thing both aircraft have in common is that they use curved windshields. I'm not sure if that adds to the black look. But what does add to the black sunglasses look is that the window frames are painted black.
Btw: There's a thread on Airliners.net where most of them seem to despise the black window frames.
The only reference regarding A350 I could find is:
The A350 XWB is the first aircraft to "wear sunglasses," referring to this jetliner’s distinctive cockpit windows.
Although from the inside, the view appears to be normal. It could probably be adjustable because on this article, you can see normal transparent windows from outside.