They share an area code, a customer segment and a history dating back to the early days of personal computing. But Apple Computer and Adobe Systems, like many in long-term relationships, have seen the 20-years-and-counting bond between them run hot and cold. Right now, it's in a colder period. Signs of frost have been accumulating for the past couple of years, with Adobe dropping Macintosh support for several software products and introducing others as Microsoft Windows-only applications. At the same time, Apple has quietly pushed Adobe out of a few markets by selling its own applications or bundling them into...