[webkit-reviews] review requested: [Bug 33150] Do not render the full frame when there is some elements with fixed positioning : [Attachment 47283] Repaint only the invalidated area after scrolling

[bugzilla-daemon at webkit.org]

Benjamin Poulain <benjamin.poulain at nokia.com> has asked  for review:
Bug 33150: Do not render the full frame when there is some elements with fixed
positioning
https://bugs.webkit.org/show_bug.cgi?id=33150

Attachment 47283: Repaint only the invalidated area after scrolling
https://bugs.webkit.org/attachment.cgi?id=47283&action=review

------- Additional Comments from Benjamin Poulain <benjamin.poulain at nokia.com>
Updated the patch with the comment of Simon

(In reply to comment #46)
> AFAICT here we are allocating the vector buffer on the speak. Once only, but
> it's still a (fastmalloc'ed) heap allocation, that is technically not needed.

> We know the size of the buffer, an allocation on the stack is cheaper,
> especially for the little amount it takes (5 pointers + alignment). 

That's a very good idea.

> Why not use Vector's inline capacity feature:
> 
>      Vector<RenderObject*, fixedObjectNumberThreshold>
fixedObjectsInViewport;
> 
> If I understand the wtf::Vector code correctly that will allocate the
vector's
> buffer nicely on the stack.

That's a very cool feature :)