Both Apple Inc.'s AAPL, +2.55% iOS and Microsoft's Windows are expected to gain market share over the next few years, while Google Inc.'s GOOGL, +4.16% GOOG, +4.20% is expected to decline slightly, according to IDC.
Analyze the relationship between 'share' and 'Windows' within the context of the input sentence.
Options: platform, headquarters location, stock exchange, currency