Gallery2: support audio effects during video play.

CRs-Fixed: 516108
CRs-Fixed: 516113
CRs-Fixed: 516114

Change-Id: I267c3c7e402fd5cf2bb223547003af491dd8289e
Gallery2: support loop/single video play mode

(cherry picked new files from commit id
990c6d43ea7c184846e19d41bef0d93aee4e581b)

Change-Id: I0f55dfdfe812262804e7e45c99c7c9bbc5fb7503