In handleEvent(), connection.receiveControlEvent() may never return
null: either it returns a valid ControlEvent, either it throws an
Exception.
Therefore, there is no need to propagate a flag to indicate whether it
returned a valid ControlEvent.
On some devices, we can reuse the same codec and display, but on some
others (e.g. Nexus 5X with Android 7.1.2), it crashes on codec.stop()
with an IllegalStateException.
Therefore, always recreate the codec and display, so that it works on
all devices.
The right-click is almost useless on Android, so use it to turn the
screen on.
Add a new control event type (command) to request the server to turn the
screen on.
Replace screenrecord execution by manual screen encoding using the
MediaCodec API.
The "screenrecord" solution had several drawbacks:
- screenrecord output is buffered, so tiny frames may not be accessible
immediately;
- it did not output a frame until the surface changed, leading to a
black screen on start;
- it is limited to 3 minutes recording, so it needed to be restarted;
- screenrecord added black borders in the video when the requested
dimensions did not preserve aspect-ratio exactly (sometimes
unavoidable since video dimensions must be multiple of 8);
- rotation handling was hacky (killing the process and starting a new
one).
Handling the encoding manually allows to solve all these problems.
