Camera: Set and get proper video size key as described in the application file.

CRs-Fixed: 343259

(cherry picked from commit 98bb823f9d2171a8d9d8331bbc3aa9972598a7a5)

Change-Id: I59b8e5d28c04baf9f0b6eef512988f5f5662c505
HAL: return pretained preview buffer to surface when preview window changed or camera disconnected.

When preview is paused due to taking snapshot, preview buffer is retained.
However, if UI changes preview window or disconnect, previous preview buffer is
not valid any more, so we need to put it back. Next time when preview is
started, it will act as a clean start of preview and get preview buffer
from display.

CR-fixed: 342926

Change-Id: I45b4580fedf523264285d0179260f13127e95bc5
Camera:Preview buffer length correction in YV12 mode also.

CRs-fixed: 343289
(cherry picked from commit 0d4758953a0c925c60f5f117bef6f719daaa9de3)

Change-Id: Ifb0a39294132db806a622eafef63931eebacf3ca