* git merge 04cb763
* See all upstream changes since the previous merge in branch aosp/upstream-master: git diff cb3f9bd..04cb763
* Modify webrtc/.gitignore to keep *.mk files.
* Removed old files from *.mk files:
- thread.cc
- thread_posix.cc
* Add new files to *.mk files:
- event_tracer.cc
* Android relevant upstream changes:
- Make Beamforming dynamically settable for Android platform builds
- Remove additional channel constraints when Beamforming is enabled in AudioProcessing
- Use an explicit identifier in Config
Change-Id: I384a4e8f6982c31c5bc70eef521bb2d90800b9a4