rAc: Make the account chooser and suggested buttons (down triangles) accessible by
keyboard navigation.

R=estade@chromium.org
BUG=260946
TEST=tab to account chooser and suggested buttons

Review URL: https://codereview.chromium.org/26584004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227851 0039d316-1c4b-4281-b951-d872f2087c98
Improve perf of CalculateDrawPropertiesInternal when there are no scroll parents.

When we have scroll parents/children, we have to, potentially, reorder the children.
Previously, we had incurred a portion of this cost, even if we didn't have any scroll
parents/children in the tree. We would still populate a vector of pointers to the
children (representing the order that they would be visited in). Of course, this
order was the same as visiting layer->children() in order, so this work is wasted.
This patch stores a bool on a layer's draw properties indicating that it has a
child with a scroll parent. If this value is false, the reordering work may be
safely skipped.

BUG=305565

Review URL: https://codereview.chromium.org/26685002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227852 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227852