Added llvm into exceptions as we can't add README.chromium into 3rd party repository

Added llvm into exceptions as we can't add README.chromium into 3rd party repository

BUG=451020
R=mnaganov@chromium.org,phajdan.jr@chromium.org

Committed: https://crrev.com/0a7adf8fde0ab0710987dd2a69293e5065c6b9a9
Cr-Commit-Position: refs/heads/master@{#317168}

[Sergiy Byelozyorov, 2015-02-19 00:47:45]

ping

[Torne, 2015-02-19 10:31:46]

torne@chromium.org changed reviewers:
+ torne@chromium.org

[Torne, 2015-02-19 10:31:47]

mnaganov is on vacation; I can help you with this.

Where is the original change that's failing with the license error? I don't
think this is the right fix; this is not the list the license checker uses. The
easiest way to check is to add the exception in the same CL that has the
problem, so the trybots will tell you if it's working, rather than landing it in
a separate CL like this.

[Torne, 2015-02-19 10:40:14]

The right thing to do is probably to add an entry to SPECIAL_CASES in
src/tools/licenses.py, which is where the existing third party directories that
are checked out directly from upstream and can't have a README.chromium added
specify their license information. You can use this file to include what would
have been in the README.chromium file if you were able to create one.

[mnaganov (inactive), 2015-02-19 20:50:08]

On 2015/02/19 10:40:14, Torne wrote:
> The right thing to do is probably to add an entry to SPECIAL_CASES in
> src/tools/licenses.py, which is where the existing third party directories
that
> are checked out directly from upstream and can't have a README.chromium added
> specify their license information. You can use this file to include what would
> have been in the README.chromium file if you were able to create one.

This change is correct. third_party/llvm is included into 'PRUNE_PATHS' in
licenses.py, because it's not shipped. But we use our own set of pruned paths,
so it is reasonable to add llvm into known_issues, which is used to build our
set. I'm not actually sure, why do we have in licenses.py SPECIAL_CASES for
libs/tools that are not shipped, but that's a different story.

Thus, lgtm.

[Sergiy Byelozyorov, 2015-02-19 23:12:40]

The CQ bit was checked by sergiyb@chromium.org

[commit-bot: I haz the power, 2015-02-19 23:14:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/935753003/1

[commit-bot: I haz the power, 2015-02-19 23:36:31]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-19 23:37:35]

Patchset 1 (id:??) landed as
https://crrev.com/0a7adf8fde0ab0710987dd2a69293e5065c6b9a9
Cr-Commit-Position: refs/heads/master@{#317168}