Oh, I checked in to filing this against webkit, itself, but I confirmed it is not an issue on any other platform so I presume it has to do with Epiphany reported of window size to the rendering engine.

Hey, this is actually missing functionality in WebKitGTK+. I have a patch ready that is waiting for a positive review here: https://bugs.webkit.org/show_bug.cgi?id=25889. Epiphany should not need to do anything special after it is landed, but I think we may prefer being explicit, so I'll leave the bug open for that.

I am tracking the upstream bug and I built webkit from source after your commit. However, the commit doesn't solve the issue. GMail still has scrollbars. I did confirm that the new build is being used in my testing.

(In reply to comment #3)
> I am tracking the upstream bug and I built webkit from source after your
> commit. However, the commit doesn't solve the issue. GMail still has
> scrollbars. I did confirm that the new build is being used in my testing.

This only happens to me for vertical bars, not for the horizontal ones.

Jason, can you upgrade to WebKitGTK+ master again and try if everything is working as expected? =)

Scrollbars on GMail windows that have a few emails are gone. However, folders/labels that have lots of emails causes the window to gain a vertical scrollbar also gain a horizontal scrollbar. The horizontal scrollbar is unexpected. It seems like the width of the body should be reported as window_width - vertical_scrollbar_width when scrolling is happening.

Actually, it appears that horizontal scroll bars do show up but randomly. It's likely another issue so I think it's safe to close this bug.

(In reply to comment #7)
> Actually, it appears that horizontal scroll bars do show up but randomly. It's
> likely another issue so I think it's safe to close this bug.

I agree. Thanks, I'll keep looking at this general problem in the future.