Utilize the input text as a context reference, choose the right relationship between share and Windows from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

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.

Answer: platform