Camera: Update storage hint in full screen state change listener.

When user swipe from gallery to camera, storage hint was not updated
based on the latest storage space. This change will call update storage
hint in full screen state change listener callback.

Change-Id: I9950cb165ae49a7d062c012f24e63898045d0c6c
CRs-fixed: 522710
Gallery2: camera: disable all camera controls ASAP when swtich the camera

Camera switch button is a pieItem, there is a fadeInOut animation for these
kinds of menus. And the onClick event deliver to upper layer happens after
the end of the animation which lasts 600ms. We should add another event
callback before the animation to disalbe all camera controls as soon as
possible.

Change-Id: Iddcb9e9452aa0ff6ea8485c08c9c56b067995fb5
Gallery2: Clear undefined buffer before first draw

Clear undefined buffer before first draw.

Crs-fixed: 526603 523916
Change-Id: I1cfdb621bdcf08dc8994adddb0111a1aaf941f56