Remove unused [RaisesException] for createNodeIterator() and createTreeWalker()

Remove unused [RaisesException] for createNodeIterator() and createTreeWalker()

While in the area, also assert that the root argument is not null, which
is guaranteed since https://codereview.chromium.org/360463005

The FIXME is removed because the whatToShow default value is 0xFFFFFFFF,
so any such warning would trigger by default.

R=haraken@chromium.org

Committed: https://crrev.com/94278580417ec6bbc7b1c99fead31b6cc448d9cb
Cr-Commit-Position: refs/heads/master@{#363850}

[philipj_slow, 2015-12-08 12:51:58]

PTAL. No dry run because the tree is in bad shape right now, but it compiles
locally.

[haraken, 2015-12-08 13:45:54]

LGTM

[philipj_slow, 2015-12-08 22:34:27]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2015-12-08 22:43:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1510753004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1510753004/1

[commit-bot: I haz the power, 2015-12-09 00:31:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-09 00:31:55]

Description was changed from

==========
Remove unused [RaisesException] for createNodeIterator() and createTreeWalker()

While in the area, also assert that the root argument is not null, which
is guaranteed since https://codereview.chromium.org/360463005

The FIXME is removed because the whatToShow default value is 0xFFFFFFFF,
so any such warning would trigger by default.

R=haraken@chromium.org
==========

to

==========
Remove unused [RaisesException] for createNodeIterator() and createTreeWalker()

While in the area, also assert that the root argument is not null, which
is guaranteed since https://codereview.chromium.org/360463005

The FIXME is removed because the whatToShow default value is 0xFFFFFFFF,
so any such warning would trigger by default.

R=haraken@chromium.org

Committed: https://crrev.com/94278580417ec6bbc7b1c99fead31b6cc448d9cb
Cr-Commit-Position: refs/heads/master@{#363850}
==========

[commit-bot: I haz the power, 2015-12-09 00:31:56]

Patchset 1 (id:??) landed as
https://crrev.com/94278580417ec6bbc7b1c99fead31b6cc448d9cb
Cr-Commit-Position: refs/heads/master@{#363850}