saza f91b0b49f9 Set memory to all-zero floats in ExtractExtendedBlock in AEC2 if buffer is empty.
This avoids a memcopy call which may corrupt audio handling and, in rare cases, crash WebRTC with a buffer over-read.

BUG=webrtc:7845

Review-Url: https://codereview.webrtc.org/2980723002
Cr-Commit-Position: refs/heads/master@{#18984}
2017-07-12 08:43:14 +00:00
..