The output of ConvolverNode in the absence of a convolution buffer

It's not clear what the output of ConvolverNode must be if the buffer
attribute is null, which is the initial state.  In Gecko we just pass
through the input.  WebKit/Blink seem to produce silence.  I think the
Gecko behavior makes more sense, and I believe that's what we should spec.

What do you think?

--
Ehsan
<http://ehsanakhgari.org/>