Stateful BoxBorderPainter

Stateful BoxBorderPainter

Refactor BoxBorderPainter to rely on local state instead of hauling a
gazillion arguments around.

Main changes:

* merge BoxBorderInfo state into BoxBorderPainter
* convert all the static methods to non-static

No functional changes are expected.

BUG=473119
R=chrishtr@chromium.org,pdr@chromium.org,junov@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=196321

[f(malita), 2015-06-02 14:19:35]

fmalita@chromium.org changed reviewers:
+ chrishtr@chromium.org, junov@chromium.org, pdr@chromium.org

[f(malita), 2015-06-02 14:30:49]

Local Telemetry runs show no impact, while CT shows a possible tiny record time
improvement (within noise levels, so take with a grain of salt):
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/f...

[chrishtr, 2015-06-02 15:37:53]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2015-06-02 15:37:54]

lgtm

[commit-bot: I haz the power, 2015-06-02 15:38:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1154213013/20001

[commit-bot: I haz the power, 2015-06-02 15:41:59]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=196321