[Meta] Left menu button not triggering exit action from WebXR

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I can only reproduce it with v72 Meta OS. The event is received as it can be seen in the logs, however the exit action is not triggered. When that happens the exit action executed with the left hand does not work either.

EDIT: note that it works the first time you exit. Subsequent actions do not exit immersive mode. I've just verified that the back action is properly detected but it is not received on Java side. Apparently there is no JNI error and the JNI invocation succeeds.

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It looks like somehow the main UI thread stops handling events. We have verified it by setting message logging in the main looper. That's why the code in runOnUiThread() is not executed and thus, Wolvic don't exit WebXR session.

It works fine if we call dispatchKeyEvent() outside the UI thread, somehow after that the main thread resumes the loop. At this point maybe it's better to wait for following beta releases (as this does not happen on any other device). In case it isn't fixed on the OS side, we would have to implement that workaround.

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So I did some more research using some perfetto tracing. What I found is that when the button stops working it's basically because the UI thread is blocked as mentioned above. The reason why it's blocked is because it's waiting in a dequeueBuffer call. This usually means that we run out of buffers and the process is waiting until there are new ones available. Still not sure why this happens.