Spinning this work out of Bug 1424095. See https://bugzilla.mozilla.org/show_bug.cgi?id=1424095#c38. We use [width] and [height] on the toolbox host iframe, the split console, and minimize mode. I had a patch to change this to use style.width and style.height but Julian pointed out at least one bug with it, so I'm moving that work out into a follow up.

Comment on attachment 8946437 [details] Bug 1434080 - WIP - Make devtools toolbox sizing use CSS properties for width/height instead of using XUL attributes; https://reviewboard.mozilla.org/r/216376/#review222164 Static analysis found 1 defect in this patch. - 1 defect found by mozlint You can run this analysis locally with: - `./mach lint check path/to/file` (Python/Javascript/wpt) If you see a problem in this automated review, please report it here: http://bit.ly/2y9N9Vx ::: devtools/client/framework/toolbox-hosts.js:125 (Diff revision 1) > > this.frame.removeEventListener("transitionend", onTransitionEnd); > this.emit("minimized"); > }; > this.frame.addEventListener("transitionend", onTransitionEnd); > - this.frame.style.marginBottom = -this.frame.height + height + "px"; > + this.frame.style.marginBottom = (height - parseInt(this.frame.style.height, 10)) + "px"; Error: Line 125 exceeds the maximum line length of 90. [eslint: max-len]