Re: [mediacapture-record] MediaRecorder needs to define effect of adding / removing tracks in its input MediaStream

@jnoring @Pehrsons Using `canvas.captureStream()` and `AudioContext.createMediaStreamDestination()` provides a means to record multiple video tracks and audio tracks into a single `Blob` "seamlessly" at both Chromium and Firefox as proven by @Kaiido, see https://bugs.chromium.org/p/chromium/issues/attachmentText?aid=328544. This should be possible using `HTMLMediaElement.captureStream()` without needing to using `requestAnimationFrame` or other means to first draw the video to the `<canvas>`. 

The could possibly be a flag included at `MediaRecorder` constructor which signals to `pause` recording when a track is added (two video tracks and two audio tracks now exist in `MediaStream`), when the previous tracks are removed (one video track and one audio track exist in `MediaStream`) `resume` recording; either internally or exposing the `resume()` call to developer. Presumably `MediaRecorder` already does this to an appreciable degree, as recording will not commence if no `MediaStreamTrack`s exist within the `MediaStream`. 

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Received on Saturday, 17 March 2018 17:05:41 UTC