VTTCue: Remove dead exception throwing code in setLine/setPosition

VTTCue: Remove dead exception throwing code in setLine/setPosition

After https://codereview.chromium.org/860353002, these checks should be
handled by the generated bindings code.

TEST=media/track/opera/interfaces/VTTCue/{line,position}.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188884

[fs, 2015-01-23 11:43:43]

fs@opera.com changed reviewers:
+ jl@opera.com, philipj@opera.com

[fs, 2015-01-23 12:40:22]

PTAL

[Jens Widell, 2015-01-23 12:59:48]

LGTM

[fs, 2015-01-23 13:08:57]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-01-23 13:09:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869173002/1

[commit-bot: I haz the power, 2015-01-23 13:31:51]

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

[commit-bot: I haz the power, 2015-01-23 13:31:54]

Failed to commit the patch.
svn: E155010: Commit failed (details follow):
svn: E155010:
'/b/infra_internal/commit_queue/workdir/blink/LayoutTests/fast/multicol/dynamic'
is scheduled for addition, but is missing

[fs, 2015-01-23 13:36:41]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-01-23 13:37:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869173002/1

[commit-bot: I haz the power, 2015-01-23 13:38:19]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188884

[philipj_slow, 2015-01-25 12:48:49]

lgtm