Corrected bug ref to failing WebRTC tests.
Corrected bug ref to failing WebRTC tests.

This used to refer back to the import bug 404303, which is circular.
Now it points to the bug to actually fix the failing tests.

BUG=404303

Review URL: https://codereview.chromium.org/1285723004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@200392 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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