Routing SuspendChange to VideoSendStream::Stats

Also checking that the statistics are properly updated in
VideoSendStreamTest.SuspendBelowMinBitrate.

Adding a test to SendStatisticsProxyTest.

Checking callback status in rampup test, too.

BUG=2457
R=mflodman@webrtc.org, pbos@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9439004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5678 4adac7df-926f-26a2-2b94-8c16560cd09d
6 files changed