Start Effects Recording only after preview loads

Start Effects Recording only after we get SurfaceTexture Callback in
EffectsRecorder, and
hence preview loaded. Disable the shutter button on creation, and
re-enable it on the preview callback. Else, one could potentially start
the recording before the preview loads, leading to a wrong state
information and an eventual crash.
Related Bugs: 5605173, 5605658

Change-Id: I2ed766997294c165ce6c262cf47f124493d0c5ec
2 files changed