Painting the title bar showed that the window's content view runs the
full height including the bar, so the shell was given a top inset to keep
clear of it. Child webviews were still being offset by the same amount on
top of that, which left a title bar's worth of empty space above every
page.
The shell and a child webview share an origin, so no correction is needed
between them: the shell pads itself, and the rect it reports is already
right. The measurement stays, for that padding only.
Vincent
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