Make overuse estimator one dimensional.

webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc

Index: webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc
index a6c182a7bc8eafcbd6f5f7d18b0de671fba43176..70051bb5fa1a8dcc31e28421585c2cafaf7c4d8a 100644
--- a/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc
+++ b/webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream_unittest.cc
@@ -52,7 +52,7 @@ TEST_F(RemoteBitrateEstimatorSingleTest, CapacityDropTwoStreamsWrap) {
 }
 
 TEST_F(RemoteBitrateEstimatorSingleTest, CapacityDropThreeStreamsWrap) {
-  CapacityDropTestHelper(3, true, 734);
+  CapacityDropTestHelper(3, true, 567);

[terelius, 2015/10/12 12:04:41]

Use of expected_drop_delta? Reason for change?

[stefan-webrtc, 2015/11/24 16:08:03]

I analyzed this and this is just a matter of timing. In all these test cases
network overuse is detected roughly at the same time, it differs roughly 10-20
ms because all streams don't start at the same time.

This together with the different start time of the streams means that the time
it takes from detection of overuse until the bandwidth estimate finally falls
below 500 kbps (which the test looks for) is a bit different. It turns out that
this case gets a sample almost exactly when it goes below 500 kbps (around 499
kbps), while the others slightly before (around 502-508 kbps).

An important difference is also that all streams are 30 fps, so a single stream
using all bandwidth means that it will only have 30 updates of the BWE per
second, while three streams may get up to 90 updates per second.

I also noted that I accidentally corrected the wrong test here. It should have
been TwoStreams.

 }
 
 TEST_F(RemoteBitrateEstimatorSingleTest, CapacityDropThirteenStreamsWrap) {