tools: Fix extensions path in check_grd_for_unused_strings.py

tools: Fix extensions path in check_grd_for_unused_strings.py

At some point extensions strings moved into extensions/strings.

BUG=none
TEST=runs

Review-Url: https://codereview.chromium.org/2802723005
Cr-Commit-Position: refs/heads/master@{#462586}
Committed: https://chromium.googlesource.com/chromium/src/+/488cf9d4df464eae28a1f1400086d3fa37ad237d

[James Cook, 2017-04-06 15:48:14]

jamescook@chromium.org changed reviewers:
+ estade@chromium.org

[James Cook, 2017-04-06 15:48:15]

estade, please take a look.

The tool crashes if a path is wrong. The other existing paths are correct. I did
not do an audit to see if there are more paths we should add.

[Evan Stade, 2017-04-06 16:23:29]

lgtm

[James Cook, 2017-04-06 17:39:29]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2017-04-06 17:40:07]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-06 19:39:40]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1491500369877780, "parent_rev":
"5a988db10ba9ed054abe390821248a795f470713", "commit_rev":
"488cf9d4df464eae28a1f1400086d3fa37ad237d"}

[commit-bot: I haz the power, 2017-04-06 19:40:31]

Description was changed from

==========
tools: Fix extensions path in check_grd_for_unused_strings.py

At some point extensions strings moved into extensions/strings.

BUG=none
TEST=runs
==========

to

==========
tools: Fix extensions path in check_grd_for_unused_strings.py

At some point extensions strings moved into extensions/strings.

BUG=none
TEST=runs

Review-Url: https://codereview.chromium.org/2802723005
Cr-Commit-Position: refs/heads/master@{#462586}
Committed:
https://chromium.googlesource.com/chromium/src/+/488cf9d4df464eae28a1f1400086...
==========

[commit-bot: I haz the power, 2017-04-06 19:40:37]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/488cf9d4df464eae28a1f1400086...