[layoutng] Create a more correct constraint space for children
At the start of layout, create a new constraint space with our size
but the existing exclusions. This will be used as the base for
layout out our children. In the future, we will call layoutOpportunities()
on this constraint space to find the correct place for our
children.
Copying the offset should not be necessary as we start with a fresh (0,0)
offset for our children, relative to us.
R=ikilpatrick@chromium.org,eae@chromium.org
BUG=635619
Review-Url: https://codereview.chromium.org/2266313002
Cr-Commit-Position: refs/heads/master@{#413817}
4 files changed
