Support for ExternalVR implementation
This PR adds the hook necessary for the ExternalVR rust-webvr driver.
Waiting on rust-webvr 0.9.3 to be published before landing.
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Remove sync constellation -> embedder communication
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Change ML search engine to duckduckgo
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Currently on Android we treat all touch events as scroll events. Servo
is already capable of distinguishing between scroll-touches and regular
touch events (see `on_touch_move` in `components/compositor/touch.rs`),
so we should just be passing touch events through.
Servo however does not natively support fling gestures, so we continue
to use `GestureDetector` for that.
Use a laser pointer rather than the trackpad to control web content
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Replace the trackpad with a laser pointer in the magicleap app.
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This improves the quality of KeyboardEvents
sent by WebDriver. Now key, code, location and
modifiers are set according to spec.
CompositionEvents are discarded as servo
does not handle them at all.
Count threads at shutdown, warn if not all finished and optionally block
On Desktop, after servo shutdown, the process exits, killing all the still-running threads.
On mobile, the process doesn't necessarily shutdown, and we are left with multiple threads failing to use channels, printing warning and panicking.
In the future, we'd like to do a clean shutdown, as in, shutdown only once all the threads have properly finished.
For now, I'm printing a warning if all the threads are not finished, and also add an option to only exit if all the threads have finished.
This only works on MacOS for now, in C, as I haven't found a Rust/multiplatform way to count running threads.
I recommend trying to run servo with `--clean-shutdown` option. Interesting to see how long it takes for other threads to shutdown, and see which threads start panicking.
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