Before this change, the test used to preload the buffer with 10 packets before starting to pull out audio. With this change, the preloading is determined by a new flag (--preload_packets) which defaults to 0. This affects all tests derived from NetEqQualityTest, i.e., all binaries called neteq_*_quality_test. Bug: none Change-Id: I920845b968a81ea9972ce8a8e646df29aff200ba Reviewed-on: https://webrtc-review.googlesource.com/49261 Reviewed-by: Alex Narest <alexnarest@webrtc.org> Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org> Cr-Commit-Position: refs/heads/master@{#21943}