Cap probing bitrate by the max bitrate instead of hardcoded 10Mbps.

Previously probing bitrate was capped at 10Mbps, which is too low for some
application. Now ProbeContoller limits max probing rate to max allowed
bitrate, which can be specified by the application.

BUG=webrtc:6332

Review-Url: https://codereview.webrtc.org/2430133005
Cr-Commit-Position: refs/heads/master@{#14927}
diff --git a/webrtc/modules/congestion_controller/probe_controller_unittest.cc b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
index fec059d..98e1166 100644
--- a/webrtc/modules/congestion_controller/probe_controller_unittest.cc
+++ b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
@@ -27,7 +27,7 @@
 
 constexpr int kMinBitrateBps = 100;
 constexpr int kStartBitrateBps = 300;
-constexpr int kMaxBitrateBps = 1000;
+constexpr int kMaxBitrateBps = 10000;
 
 constexpr int kExponentialProbingTimeoutMs = 5000;
 
@@ -67,6 +67,9 @@
 TEST_F(ProbeControllerTest, TestExponentialProbing) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
+
+
+
   EXPECT_CALL(pacer_, CreateProbeCluster(2 * 1800, _));
   probe_controller_->SetEstimatedBitrate(1800);
 }