audio_processing/aec: Increased delay metrics aggregation window to five seconds
audio_processing/aec: Increased delay metrics aggregation window to five seconds

The known clients (GetStats and UMA histogram in Chrome) use at least 5 second aggregation window. There is no particular value in calculating the metrics more often.

The CL also includes a small refactoring moving a declaration inside an if statement.

BUG=2994
TEST=N/A
R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/40219004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@8619 4adac7df-926f-26a2-2b94-8c16560cd09d

svn2github/webrtc-Revision-8758,svn2github/webrtc-Revision-8758,svn2github/webrtc-Revision-8758,svn2github/webrtc-Revision-8758,svn2github/webrtc-Revision-8758,svn2github/webrtc-Revision-8758