This problem appears to have been a Chrome bug which was subsequently fixed: https://bugs.chromium.org/p/chromium/issues/detail?id=518863
Closing as this should not happen any more, please file a new report following all the guidelines if you still have any issues.
Well not totally. The sound can still be lost if no sound was playing before device going to sleep. Issue on Chromium: https://bugs.chromium.org/p/chromium/is ... 1462478611