Snap: Allow quickreader to work with secure device

* Mimic the behaviour from CameraActivity to allow using the quickreader
  activity with locked screen
* Pass the value if mSecureCamera as SECURE_CAMERA_EXTRA flag to get
  knowledge if the WindowManager flags have to be modified
* Also tested: Scanning an url doesn't allow bypassing the lockscreen, so
  it's only the reader itself which will work with a locked device

Change-Id: Ia9da7b712f5e5aab32a49d272e3d42651dee412d
2 files changed