The volume slider has 0.01 step so that VO adjusts it very slowly. Also the value should be spoken in a percentage. <rdar://problem/27285070>
Created attachment 284385 [details] Patch
Created attachment 284450 [details] patch Changed the step to 0.05
Comment on attachment 284450 [details] patch Clearing flags on attachment: 284450 Committed r203669: <http://trac.webkit.org/changeset/203669>
All reviewed patches have been landed. Closing bug.