Apple Inc. CEO Tim Cook walks past an iOS7 logo during the Apple Worldwide Developers Conference (WWDC) 2013 in San Francisco, California, June 10, 2013. [Photo/Agencies]

Phil Schiller, senior vice-president of worldwide marketing at Apple Inc., introduces the new Mac Pro during Apple Worldwide Developers Conference (WWDC) 2013 in San Francisco, California, June 10, 2013. [Photo/Agencies]