GitLab

r296008 regressed TooltipAura vertical placement.
(that change removed vertical centering of multi-line text)
(TooltipAura implicitly used this for vertical padding)

Add an actual border and explicit Label sizing instead.
(this allocates space for the padding in the Label border)
(it also base-line centers the text in the correct bounds)

See before/after pics at http://crbug.com/417602#c5

BUG=417602
TEST=Chrome OS and "Windows 8 mode" Chrome tooltips look good.
R=sky@chromium.org

Review URL: https://codereview.chromium.org/602313002

Cr-Commit-Position: refs/heads/master@{#296874}