UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.75 Safari/537.36

Example URL:
https://jsfiddle.net/3dw9g07p/

Steps to reproduce the problem:
1. Visit https://jsfiddle.net/3dw9g07p/ 
2. Observe in Chrome 49 that the first two lines match despite the first one (HTML) having different letter-spacing than the second one (SVG).
3. Further observe that the first and last lines do not match despite having the same letter-spacing.

What is the expected behavior?
The first and last lines should have the same letter-spacing. 

What went wrong?
It seems that letter-spacing for SVGs is off by 50%. The SVG span with 10px letter-spacing matches the HTML span with 15px letter-spacing.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? Yes Chrome 48

Does this work in other browsers? Yes 

Chrome version: 49.0.2623.75  Channel: n/a
OS Version: OS X 10.10.5
Flash Version: Shockwave Flash 20.0 r0

Safari renders this as expected.

At Benchling, we render text using SVGs, relying on precise measurements for font-size and letter-spacing to ensure other UI elements properly align with the text (e.g. https://benchling.com/s/SAMPLEPLASMID ). 

The only reasonable workarounds I can currently see are to either detect the letter-spacing issue and correct for the 50% increase, or avoid using letter-spacing until the bug is fixed.