This is a rollup of three separate patches
- Add nsIDocShell.asyncPanZoomEnabled. r=jlebar
- Have BrowserElementChild service repaint requests and handle fallback synchronous scrolling (for now). r=jlebar,vingtetun
- Glue async pan/zoom logic up between compositing, event dispatch, and repaint requests. r=roc
--HG--
rename : b2g/chrome/content/webapi.js => dom/browser-element/BrowserElementScrolling.js