Add base class NetworkPredictor and NetworkPredictorFactory and wire up.

Add base class NetworkPredictor and NetworkPredictorFactory in /api, make it possible to inject customized NetworkPredictor in PeerConnectionFactory level. The NetworkPredictor object will be pass down to GoogCCNetworkControl and DelayBasedBwe.

Bug: webrtc:10492
Change-Id: Iceeadbe1c9388b11ce4ac01ee56554cb0bf64d04
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/130201
Commit-Queue: Ying Wang <yinwa@webrtc.org>
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27543}

modules/remote_bitrate_estimator/BUILD.gn

@@ -41,6 +41,7 @@ rtc_static_library("remote_bitrate_estimator") {
 
   deps = [
     "../..:webrtc_common",
+    "../../api:network_state_predictor_api",
     "../../api:rtp_headers",
     "../../api/units:data_rate",
     "../../api/units:timestamp",

modules/remote_bitrate_estimator/include/bwe_defines.h

@@ -14,6 +14,7 @@
 #include <stdint.h>
 
 #include "absl/types/optional.h"
+#include "api/network_state_predictor.h"
 #include "api/units/data_rate.h"
 
 #define BWE_MAX(a, b) ((a) > (b) ? (a) : (b))
@@ -38,13 +39,6 @@ enum BweNames {
   kBweNamesMax = 4
 };
 
-enum class BandwidthUsage {
-  kBwNormal = 0,
-  kBwUnderusing = 1,
-  kBwOverusing = 2,
-  kLast
-};
-
 enum RateControlState { kRcHold, kRcIncrease, kRcDecrease };
 
 struct RateControlInput {

modules/remote_bitrate_estimator/test/estimators/send_side.cc

@@ -38,7 +38,7 @@ SendSideBweSender::SendSideBweSender(int kbps,
           absl::make_unique<AcknowledgedBitrateEstimator>(
               &field_trial_config_)),
       probe_bitrate_estimator_(new ProbeBitrateEstimator(nullptr)),
-      bwe_(new DelayBasedBwe(&field_trial_config_, nullptr)),
+      bwe_(new DelayBasedBwe(&field_trial_config_, nullptr, nullptr)),
       feedback_observer_(bitrate_controller_.get()),
       clock_(clock),
       send_time_history_(10000),