Fix paint invalidation for SVG with outline-offset

Fix paint invalidation for SVG with outline-offset

The paint invalidation code did not factor in the outline-offset,
leading to too small repaint rectangles.
Use ComputedStyle::outlineSize() when inflating the paint invalidation
rect instead. If the outline-style is 'auto', then use the
GC::focusRingOutsetExtent function - this leads to smaller paint inv.
rects where this applies (like in tests svg/repaint/focus-element.html
and svg/custom/focus-ring.svg).

BUG=495666
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196484

[fs, 2015-06-03 16:15:58]

fs@opera.com changed reviewers:
+ fmalita@chromium.org, pdr@chromium.org

[f(malita), 2015-06-03 20:26:04]

lgtm

[fs, 2015-06-04 09:07:19]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-06-04 09:07:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1157843008/1

[commit-bot: I haz the power, 2015-06-04 09:11:07]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196484