[webkit-reviews] review requested: [Bug 23556] On RTL pages, horizontal scrollbar is missing : [Attachment 29675] A workaround fix

[bugzilla-daemon at webkit.org]

Hironori Bono <hbono at chromium.org> has asked  for review:
Bug 23556: On RTL pages, horizontal scrollbar is missing
https://bugs.webkit.org/show_bug.cgi?id=23556

Attachment 29675: A workaround fix
https://bugs.webkit.org/attachment.cgi?id=29675&action=review

------- Additional Comments from Hironori Bono <hbono at chromium.org>
As far as I investigated on my MacBook, it is an edge-case problem caused by
discrepancy (sorry, I cannot figure out any better words) between FrameView and
RenderBlock.
FrameView trims the left side of its children when their offsetLeft is
negative. (It is an expected behavior.) On the other hand,
RenderBlock::determineHorizontalPosition may set a negative value to the
offsetLeft value of an RTL element wider than the window width. (It is also an
expected behavior.)
So, when FrameView has a child RTL element wider than the window width,
RenderBlock::determineHorizontalPosition set a negative value to the offsetLeft
value of the RTL element and FrameView trims its left side without displaying a
horizontal scrollbar.

Even Though I'm not confident this is a right fix, I wrote a workaround fix and
a layout test for this case.