The work isn't a surprise, given that Google created mock-ups of a Chrome OS tablet more than a year ago. But it does indicate that a tablet incarnation of Google's Web-app operating system is a near-term priority, not just an idea.
Google acknowledged the tablet version of Chrome OS but wouldn't discuss details such as when the project's first version will be done. "We are engaging in early open-source work for the tablet form factor, but we have nothing new to announce at this time," the company said in a statement.
Chrome OS tablets, though, are not first on the list, the company said: "Chrome OS was designed from the beginning to work across a variety of form factors. We expect to see different partners build different kinds of devices based on Chrome OS, but for this initial release we are targeting the notebook form factor."
Chrome OS has been evolving since Google announced it in 2009. Initially it was aimed at Netbooks, the small, low-end laptops. But the first incarnation of Chrome OS--a pilot release intended for developers and testers rather than ordinary customers--arrived in a more polished laptop package called the Cr-48.
A tablet version of Chrome OS, though, raises a big question about Google's strategy, because the company's tablet version of the Android operating system, Honeycomb, is just now arriving on the market with Motorola's Xoom and other products designed to compete with the leader of the tablet market, Apple's iPad.
Signs of Chrome OS for tablets
A number of changes in Chrome and Chrome OS source code that arrived in March and April reveal the tablet work. Among them:
- The "user-agent string" text that browsers supply so Web servers can deliver the appropriate version of a Web site--for touch user interfaces. The string includes the term "CrOS Touch," not just CrOS as before. "This lets Web sites that are already customizing for tablet experiences easily adapt to support tablet ChromeOS devices," the programming change log notes.
- A "virtual keyboard" with a number of keys--tab, delete, microphone, return, and shift, for example--drawn in SVG so they can be shown by a browser. Screen keyboards are, of course, a necessity with tablets.
- A variety of moves to make the browser more touch-friendly, for example by increasing the space around items to make it easier to select them with a touch interface.
- A revamped new-tab page (which people see when they open a new, blank tab) that's "optimized for touch." The current page shows an array of Web applications downloaded from the Chrome Web Store, but the modified version adds multiple screens of icons in the style of iOS devices.
The orientation of the new-tab page, but not its size, will change when the device is rotated, according to the new-tab page's coding annotations. "Note that this means apps will be reflowed when rotated (like iPad)," the annotation said.
The CSS code for the new-tab page also indicates that programmers would like to be able to move icons around the page, preferably with animation.