Revert 5775 "Modify bitrate controller to update bitrate based o..."

This triggered an occasional TSAN failure in
CallTest.ReceivesPliAndRecoversWithNack e.g.:
http://build.chromium.org/p/client.webrtc/builders/Linux%20Tsan/builds/1444/steps/memory%20test%3A%20video_engine_tests/logs/stdio

I managed to reproduce this locally and verified that reverting this CL
corrected it.

> Modify bitrate controller to update bitrate based on process call and not
> only whenever a RTCP receiver block is received.
> 
> Additionally:
>  Add condition to only start rampup after a receiver block is received. This was same as old behaviour but now an explicit check is needed to verify process does not ramps up before the first block.
> 
>  Fix logic around capping max bitrate increase at 8% per second. Before it was only increasing once every 1 second and each increase would be as high as 8%. If receiver blocks had a different interval before it would lose an update or waste an update slot and not ramp up as much as a 8% (e.g. if RTCP received < 1 second).
> 
>  Did not touch decrease logic, however since it can be triggered more often it
>  may decrease much faster and closer to the original written cap of once every
>  300ms + rtt.
> 
> Note:
>  rampup_tests.cc don't seem to be affected by this since there is no packet loss or REMB that go higher than expected cap.
>  bitrate_controller_unittests.cc are don't really simulate a clock and the process thread, but trigger update by inserting an rtcp block.
> 
> BUG=3065
> R=stefan@webrtc.org, mflodman@webrtc.org
> 
> Review URL: https://webrtc-codereview.appspot.com/10529004

TBR=andresp@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/10079005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5785 4adac7df-926f-26a2-2b94-8c16560cd09d
8 files changed