Change request: playbackPosition attribute for AudioBufferSourceNode

Hi,

AudioBufferSourceNode is missing a playbackPosition attribute that
is essential for wave views and playback position displays. We think
it requires only a simple change to the code. What's is the procedure for
change requests?


Proposed additions:

AudioBufferSourceNode.h:
float playbackPosition() { return m_virtualReadIndex / sampleRate; }

AudioBufferSourceNode.idl:
readonly attribute float playbackPosition;

Thanks,

Rob Clouth