Google helped make Adobe Systems' PDF files a first-class citizen on the Web years ago by indexing their content with its search engine. Now it's gone another step by building the ability to read them into its latest browser, Chrome 8, released yesterday for Windows, Mac, and Linux.

That means when people click a PDF link, the document will open directly in the browser. Chrome's built-in PDF reader is also walled up within a sandbox, lowering the risk that security issues will escape a confined region of memory to facilitate a broader attack on a computer.

The PDF reader is among 800 improvements in Chrome 8, including 12 security fixes, according to a blog post yesterday by Chrome team member Jason Kersey. Google paid out $1,000 to each of three discoverers of high-risk vulnerabilities and $500 to two discovers of medium-risk vulnerabilities.

Chrome 8 also is the first version to support the Chrome Web Store, Google has said. However, there aren't any direct signs yet that it's tapping into the upcoming Google service for finding and selling Web applications, Chrome extensions, and Chrome themes.

Adobe is working to improve PDF without Chrome, too. Its latest Reader 9 and Acrobat X software has a browser plug-in that hides the application frame that previously surrounded PDF documents viewed in a browser.

The new Chrome 8.0.552.215 replaces both the earlier beta and stable versions. It arrives just about six weeks after Google released Chrome 7' the faster release pace this year means new Chrome versions aren't necessarily as big of a departure from their predecessors. For those with a taste for cutting-edge features but less stability, there's the Chrome Dev channel, which is on the 9.x release version.

New for Windows users of Chrome Dev is a sandboxed version of Adobe's Flash Player, an oft-cited culprit in browser crashes and security vulnerabilities. Building Flash and PDF readers into Chrome means, among other things, that they will be upgraded rapidly and typically invisibly whenever Google wants to distribute a new version for performance, features, or security reasons.

Chrome's PDF reader appears to use the Foxit PDF SDK software, but the built-in Flash Player is from Adobe.

"For initial testing, the sandboxing code currently supports Windows XP, Windows Vista, and Windows 7. There are plans to make this available for all OS platforms once we are further along in testing and development," Adobe Flash team member Peleus Uhley said in a blog post this week. "We hope that we can use this experience as a platform for discussing sandbox approaches with the other browser vendors."

Also on tap for Chrome 9 is a lot of hardware acceleration work, including accelerated 3D graphics with the WebGL interface.