Incorrect invalidation on Google Forum

Incorrect invalidation on Google Forum

The issue was that we would generate incremental invalidations for
a positioned element instead of a full invalidation. This is
because the repaint rect didn't move when intersected with the
overflow clip.

The fix is to force positioned children of a positioned element
that required a positioned movement layout to be relaid out. This
is similar to what was done in
https://codereview.chromium.org/192863004. To achieve the previous
fix, we make positioned movement layout do a simplified layout,
which simplifies the code by removing the possibility of doing
both independently.

BUG=360524
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=172042

[leviw_travelin_and_unemployed, 2014-04-17 20:35:55]

LGTM with a nit.

https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
File Source/core/rendering/RenderBlock.cpp (right):

https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
Source/core/rendering/RenderBlock.cpp:1526: if ((!posChildNeedsLayout() &&
!(needsSimplifiedNormalFlowLayout() || needsPositionedMovementLayout())) ||
normalChildNeedsLayout() || selfNeedsLayout())
This conditional is really hard to work out. Could we give the set of
conditionals a name or comment explaining what it's supposed to do?

[Julien - ping for review, 2014-04-18 18:20:31]

https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
File Source/core/rendering/RenderBlock.cpp (right):

https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
Source/core/rendering/RenderBlock.cpp:1526: if ((!posChildNeedsLayout() &&
!(needsSimplifiedNormalFlowLayout() || needsPositionedMovementLayout())) ||
normalChildNeedsLayout() || selfNeedsLayout())
On 2014/04/17 20:35:55, Levi wrote:
> This conditional is really hard to work out. Could we give the set of
> conditionals a name or comment explaining what it's supposed to do?

Split the logic and added some comment to make more obvious what's going on.

[leviw_travelin_and_unemployed, 2014-04-18 18:52:41]

On 2014/04/18 18:20:31, Julien Chaffraix - PST wrote:
>
https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
> File Source/core/rendering/RenderBlock.cpp (right):
> 
>
https://codereview.chromium.org/241113004/diff/1/Source/core/rendering/Render...
> Source/core/rendering/RenderBlock.cpp:1526: if ((!posChildNeedsLayout() &&
> !(needsSimplifiedNormalFlowLayout() || needsPositionedMovementLayout())) ||
> normalChildNeedsLayout() || selfNeedsLayout())
> On 2014/04/17 20:35:55, Levi wrote:
> > This conditional is really hard to work out. Could we give the set of
> > conditionals a name or comment explaining what it's supposed to do?
> 
> Split the logic and added some comment to make more obvious what's going on.

Thank you! This is clearer to me :)

[Julien - ping for review, 2014-04-21 16:25:15]

The CQ bit was checked by jchaffraix@chromium.org

[commit-bot: I haz the power, 2014-04-21 16:25:21]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jchaffraix@chromium.org/241113004/40001

[commit-bot: I haz the power, 2014-04-21 16:36:33]

Change committed as 172042