Consider RTL layout in DPAD navigation in AbsSeekBar

Changes the behavior of onKeyDown for DPAD_LEFT/RIGHT when in RTL
to move the progress in same direction as the DPAD key suggest.

Change-Id: I776a48711571884a10ef9315de78bf4ebffd6e4b
Merge "Consider RTL layout in DPAD navigation in AbsSeekBar"