Untracked headers fly under the 'gn check' radar and in the long term this can cause problems like unnoticed cyclic dependencies. This cl creates a synthetic target for this header since no other targets in webrtc/modules/pacing/BUILD.gn seem to be related to it. BUG=webrtc:7649 NOTRY=True Review-Url: https://codereview.webrtc.org/2887593003 Cr-Commit-Position: refs/heads/master@{#19656}