It's only a problem when you squeeze out competition by doing exclusive contracts with all major distributors in a particular distribution channel.
However, the point was that Chrome didn't mysteriously gain market share solely based on some sort of technical superiority.
Google paid to gain market share with the sorts of clueless users who click next during install wizards without reading anything.
Although, it helps to remember that in the EU, you don't need nearly as big a market share before their competition law kicks in and places restrictions on your behavior, so things that you can still get away with in the US can be quite illegal in the EU.