There is currently no checks for rectangle height and width being set to only non-negative numbers, and we have code that clearly assumes those values are allowed (at least temporarily). Remove the asserts from the Set{Right,Left,Bottom,Top}Edge methods that trigger if the width/height are set to a negative value to make things consistent. If we decide that the negative values should never be allowed, we need to make larger changes. With these asserts, we're discouraging the use of these convenient methods, instead forcing callers to compute and set the width and height directly.

Comment on attachment 8940208 [details] Bug 1428348: Allow Set{Left,Right,Top,Bottom}Edge methods to compute negative width/height without asserting. .schouten https://reviewboard.mozilla.org/r/210522/#review217156

Pushed by msreckovic@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/fe793fde1117 Allow Set{Left,Right,Top,Bottom}Edge methods to compute negative width/height without asserting. r=bas.schouten