Expose the capture-side AudioProcessing object and allow it to be injected.

* Clean up the configuration code, including removing most of the weird defines.
* Add a unit test.

Review URL: https://webrtc-codereview.appspot.com/1152005

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3605 4adac7df-926f-26a2-2b94-8c16560cd09d
11 files changed