Bug 835809: Preload more things for faster page loads. r=fabrice,jlebar

--HG--
rename : dom/browser-element/BrowserElementChild.js => dom/browser-element/BrowserElementChildPreload.js
rename : dom/browser-element/BrowserElementScrolling.js => dom/browser-element/BrowserElementPanning.js
Bug 836072 - Validate the arguments to AudioParam.exponentialRampToValueAtTime() correctly; r=roc
Back out 6a5dcf166f09 (bug 836072) for build bustage
CLOSED TREE
Bug 838745 - Prevent crashing if a promo type is dropped r=bnicholson
Bug 839242 - Remove unused onunload handler from about:apps r=margaret