Implement "auto -> angle" animation on <marker> orient attribute.

Implement "auto -> angle" animation on <marker> orient attribute.

Before this CL, "angle -> auto" animation was implemented but "auto -> angle"
animation was not implemented. This CL implements the missing piece as
a discrete animation as specified in the spec.

BUG=425848
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=184260

[kouhei (in TOK), 2014-10-23 06:13:22]

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

[kouhei (in TOK), 2014-10-23 06:13:23]

Would you take a look?

[fs, 2014-10-23 08:26:23]

lgtm

[kouhei (in TOK), 2014-10-23 08:27:08]

The CQ bit was checked by kouhei@chromium.org

[commit-bot: I haz the power, 2014-10-23 08:27:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/672853002/1

[commit-bot: I haz the power, 2014-10-23 10:13:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-10-23 10:13:44]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/33235)

[kouhei (in TOK), 2014-10-23 10:14:07]

The CQ bit was checked by kouhei@chromium.org

[commit-bot: I haz the power, 2014-10-23 10:14:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/672853002/1

[commit-bot: I haz the power, 2014-10-23 12:17:36]

Committed patchset #1 (id:1) as 184260