[CSS Shapes] Empty polygons with non-zero shape-padding cause an ASSERT crash

[CSS Shapes] Empty polygons with non-zero shape-padding cause an ASSERT crash

PolygonShape::shapePaddingBounds() and PolygonShape::shapeMarginBounds() no longer attempt to compute a new FloatPolygon when the original is empty, i.e. when it has less than three vertices.

This patch fixes the clusterfuzz failure reported here: https://code.google.com/p/chromium/issues/detail?id=314402

BUG=319069, 314402
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=161996

[Hans Muller, 2013-11-14 03:30:01]

I've fixed the crash reported by clusterfuzz
https://code.google.com/p/chromium/issues/detail?id=314402

[eseidel, 2013-11-14 04:09:59]

lgtm

[commit-bot: I haz the power, 2013-11-14 04:10:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hmuller@adobe.com/68263018/60001

[eseidel, 2013-11-14 04:10:36]

You can list multiple numbers on the BUG= line and then the bug bot will be
smart enough to update both bugs when this lands. :)

[commit-bot: I haz the power, 2013-11-14 06:34:35]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[commit-bot: I haz the power, 2013-11-14 06:37:55]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hmuller@adobe.com/68263018/60001

[commit-bot: I haz the power, 2013-11-14 06:38:59]

Change committed as 161996