1447864 - Resize newly-opened window with size from features before its initial layout

Status: NEW

(Core :: XUL, enhancement, P5)

Description

[Xidorn Quan [:xidorn] UTC+11]

When content open a new popup with features like left/top/width/height, we open the new window and do layout with the size and position inherited from its opener (due to persistence on browser window), and resize / reposition it afterwards.

This means we are wasting an extra resize reflow on for window with those features.

Specifically, in nsWindowWatcher::OpenWindowWithTabParent, we call into CreateChromeWindow which does the initial layout, and only after that we call SizeOpenedWindow to resize according to specified window features.

We probably should back SizeOpenedWindow somehow into CreateChromeWindow directly to save the resize reflow there.

Also this would block bug 1446264 since if we cannot size the window before we take the persisted values, there may be some flicking due to showing window aggressively by part 3 in that bug.