UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36

Example URL:
http://bl.ocks.org/stestagg/aa6db5d177b09e74825c6e4b02cb3f07

Steps to reproduce the problem:
1. Fill an element with a long (>10k character) string of data (for example, a base-64 encoded image)
2. Set the css style word-break: break-all on it
3. Wait for the DOM to update

What is the expected behavior?
The update happens in a reasonable time (probably < 1s)

What went wrong?
Updating the layout for elements with the above content/styling can easily take > 30s, during which time, the entire page is unresponsive

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes 

Chrome version: 51.0.2704.103  Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 22.0 r0

The above, (deeply non-scientific) script has been tested on:

Windows 7: Firefox, Chrome, IE 9
Windows 10: Chrome 51, Edge
OSX: Firefox, Safari, Chrome 52

Both Windows 7 & 10 Chrome exhibit very poor behaviour (between 7.5 and ~20s to lay out 32k chars)
Chrome on OSX shows non-linear behaviour, but ~65ms for 32k
Safari on OSX is also non-linear, up to ~600ms for 32k chars

Firefox, Edge, and IE all show essentially zero layout cost 32k chars (between 16 and 30 ms)