[webkit-reviews] review requested: [Bug 81786] Support fixed position elements in Qt WebKit2 : [Attachment 134995] Patch

[bugzilla-daemon at webkit.org]

Yael <yael.aharon at nokia.com> has asked	for review:
Bug 81786: Support fixed position elements in Qt WebKit2
https://bugs.webkit.org/show_bug.cgi?id=81786

Attachment 134995: Patch
https://bugs.webkit.org/attachment.cgi?id=134995&action=review

------- Additional Comments from Yael <yael.aharon at nokia.com>
This patch has a somewhat different approach. It does not pass Length
information to the UI, and relies on the web process to calculate the position.
This patch still passes information about which edges have fixed position.

TextureMapperLayer::adjustedScrollOffset does 2 things now:
1. During scroll overshoot, we want the fixed layer to move with the edge only
if it is fixed to that edge. so it checks and adjusts for that.(Same behavior
as iOS5).
2. Due to async nature of the messages, during scrolling, the UI and the web
process might use different scroll offsets, so it checks and compensates for
that too.

Currently, when we zoom, fixed position elements are not positioned correctly,
and this patch does _not_ address that behavior.