Avoid forcing layout on children with orthogonal flow

Avoid forcing layout on children with orthogonal flow

Flexbox always sets an override size on its children, and
keying off that, we force layout in preferredMainAxisContentExtentForChild
to get the preferred logical height. This patch caches that
value, and only re-lays out the child when necessary.

The original version of this patch was authored by abarth,
whose original patch uncovered a bug that was masked by
the additional layout. resetAutoMarginsAndLogicalTopInCrossAxis
previously reset the logical top but not auto margins.
This would cause us to double-count cross-axis margins
later on.

BUG=333116
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=165162

[ojan, 2014-01-14 22:05:01]

https://codereview.chromium.org/138683005/diff/30007/LayoutTests/css3/flexbox...
File LayoutTests/css3/flexbox/repaint-opacity-change.html (right):

https://codereview.chromium.org/138683005/diff/30007/LayoutTests/css3/flexbox...
LayoutTests/css3/flexbox/repaint-opacity-change.html:22: .btn {
Wat?

https://codereview.chromium.org/138683005/diff/30007/Source/core/rendering/Re...
File Source/core/rendering/RenderFlexibleBox.cpp (right):

https://codereview.chromium.org/138683005/diff/30007/Source/core/rendering/Re...
Source/core/rendering/RenderFlexibleBox.cpp:645: if (child->hasOverrideWidth()
|| child->hasOverrideHeight())
I think you can unconditionally call clearOverrideSize and save a couple hash
table lookups.

[leviw_travelin_and_unemployed, 2014-01-14 22:39:27]

PTAL

On 2014/01/14 22:05:01, ojan wrote:
>
https://codereview.chromium.org/138683005/diff/30007/LayoutTests/css3/flexbox...
> File LayoutTests/css3/flexbox/repaint-opacity-change.html (right):
> 
>
https://codereview.chromium.org/138683005/diff/30007/LayoutTests/css3/flexbox...
> LayoutTests/css3/flexbox/repaint-opacity-change.html:22: .btn {
> Wat?

Cleaned up :)

> 
>
https://codereview.chromium.org/138683005/diff/30007/Source/core/rendering/Re...
> File Source/core/rendering/RenderFlexibleBox.cpp (right):
> 
>
https://codereview.chromium.org/138683005/diff/30007/Source/core/rendering/Re...
> Source/core/rendering/RenderFlexibleBox.cpp:645: if (child->hasOverrideWidth()
> || child->hasOverrideHeight())
> I think you can unconditionally call clearOverrideSize and save a couple hash
> table lookups.

Done!

[leviw_travelin_and_unemployed, 2014-01-15 18:35:05]

ping

[ojan, 2014-01-15 18:48:49]

lgtm

Huh...apparently I forgot to publish my comments. :( I blame rietveld.

https://codereview.chromium.org/138683005/diff/110001/Source/core/rendering/R...
File Source/core/rendering/RenderFlexibleBox.h (right):

https://codereview.chromium.org/138683005/diff/110001/Source/core/rendering/R...
Source/core/rendering/RenderFlexibleBox.h:160: HashMap<const RenderObject*,
LayoutUnit> m_intrinsicSizeAlongMainAxis;
I wonder if we can come up with a better name for this as it's only for
orthogonal flows and certain flex-basis values. I'm having trouble coming up
with anything though.

[commit-bot: I haz the power, 2014-01-15 19:09:16]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/leviw@chromium.org/138683005/240001

[commit-bot: I haz the power, 2014-01-15 21:42:35]

Change committed as 165162