What is SVGGraphicsElement.getBBox() expected to return for textPaths and tspans?

Hi all!

I'm Sebastian and it's the first time I'm writing here.

Short summary of why I'm writing:
I first discussed the behavior of SVGGraphicsElement.getBBox() in a Mozilla
bug[1]. This lead me to a Chromium bug[2], which itself refers to some SVG
telcon minutes[3]. The resolution in those minutes is not clear to me,
though.

So, I have two questions:
Is getBBox() expected to return the bounding box of the surrounding <text>
element when called on  a <textPath> or <tspan> element? (See the test
cases attached to the Mozilla and Chromium bug.)
Shouldn't getBBox() be deprecated in favor of
Element.getBoundingClientRect()[4]?

Best regards,

Sebastian

[1] https://bugzil.la/937268
[2] https://code.google.com/p/chromium/issues/detail?id=349835
[3] https://www.w3.org/2014/04/07-svg-minutes.html#item05
[4] https://drafts.csswg.org/cssom-view/#dom-element-getboundingclientrect