This fixes an error when loading the diff viewer on release-5.0.x (and

master). Devtools were showing an error that the DiffViewerPage

constructor wasn't a constructor. The issue here seems to be a change in

the way that the newer babel deals with function shorthands inside of an

object. Whereas before it was translating constructor() {...} to

constructor: function constructor() {...}, it now leaves them as-is.

In most cases this works fine, but it seems like browsers are treating

the constructor name specially (since it's a reserved word and used

for classes). Explicitly using the older object attribute syntax fixes

this.

Created a review request with a diff and was able to successfully load

the diff viewer page.