The diff complexity icon had some performance issues that manifested

when working with larger files. When rendering the icon, we get the line

counts for each type of diff chunk (inserts, deletes, replaces, equals)

and pass them to flot. It turns out that the higher the numbers you

provide, the more flot has to do to render the graph, despite the graph

being a small basic pie chart.
To address the performance issue, we now normalize the values ourselves,

scaling down the totals to cap to 365 and ensuring all the segments are

of the correct percentage of that total.
We also have a performance improvement in the code that calculates the

colors. It was building a DOM element and attaching it to the document,

getting the styles from that, and then removing it. That could impact

rendering time of the page, and if the browser was otherwise very busy

(placing a very large diff on the page, for instance), color calculation

could take too long. We now make sure this is hidden before attaching to

the document, which avoids the rendering penalties.
This can make a significant impact on the rendering performance of the

diff viewer.

Tested with very large diffs and measured the performance. There was a

significant drop in rendering time.
Compared the rendered icons between the old and new code for about 15

diffs of various sizes. The renders were identical.