Greatly improve Firefox's performance with this demo.
- Uses runtime messaging to communicate page scrolls
- Uses
tabs.captureVisibleTab()
to the top of the page - Uses a slightly modified version of stackblur.js to blur the capture
- Uses
theme.update(windowId, {headerURL: ...})
to update the browser theme
- original version of stackblur.js: http://quasimondo.com/StackBlurForCanvas/StackBlurDemo.html