camera2: Avoid spurious IDLE transitions.

Bug: 17594247

- Avoid spurious IDLE transitions when waiting for
  prior requests to complete.
- Clean up error reporting for GL thread and CameraDeviceState.
- Add error handling for Camera1 ErrorCallback calls.

Change-Id: I72850251d8965139b6db2193e91483a3d3409b7c
4 files changed