Move VideoStreamReceiver JSON configuration parser to test source_set.

This change moves the configuration parser that converts a JSON representation
of the VideoStreamReceiver::Config structure into a native object into the test
directory so that it can be shared with the new corpus_generator utility that is
being built. This rtc_source_set will have an additional utility function added
in a subsequent CL that will allow the generation of a VideoStreamSender::Config
from a given VideoStreamReceiver::Config and visa versa.

Bug: webrtc:10117
Change-Id: I3035826f799f8d1fcdeaa76997391f030c855a5c
Reviewed-on: https://webrtc-review.googlesource.com/c/116880
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Commit-Queue: Benjamin Wright <benwright@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26252}
diff --git a/test/call_config_utils.cc b/test/call_config_utils.cc
new file mode 100644
index 0000000..48d4849
--- /dev/null
+++ b/test/call_config_utils.cc
@@ -0,0 +1,72 @@
+/*
+ *  Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "test/call_config_utils.h"
+
+#include <string>
+#include <vector>
+
+namespace webrtc {
+namespace test {
+
+// Deserializes a JSON representation of the VideoReceiveStream::Config back
+// into a valid object. This will not initialize the decoders or the renderer.
+VideoReceiveStream::Config ParseVideoReceiveStreamJsonConfig(
+    webrtc::Transport* transport,
+    const Json::Value& json) {
+  auto receive_config = VideoReceiveStream::Config(transport);
+  for (const auto decoder_json : json["decoders"]) {
+    VideoReceiveStream::Decoder decoder;
+    decoder.video_format =
+        SdpVideoFormat(decoder_json["payload_name"].asString());
+    decoder.payload_type = decoder_json["payload_type"].asInt64();
+    for (const auto& params_json : decoder_json["codec_params"]) {
+      std::vector<std::string> members = params_json.getMemberNames();
+      RTC_CHECK_EQ(members.size(), 1);
+      decoder.video_format.parameters[members[0]] =
+          params_json[members[0]].asString();
+    }
+    receive_config.decoders.push_back(decoder);
+  }
+  receive_config.render_delay_ms = json["render_delay_ms"].asInt64();
+  receive_config.target_delay_ms = json["target_delay_ms"].asInt64();
+  receive_config.rtp.remote_ssrc = json["rtp"]["remote_ssrc"].asInt64();
+  receive_config.rtp.local_ssrc = json["rtp"]["local_ssrc"].asInt64();
+  receive_config.rtp.rtcp_mode =
+      json["rtp"]["rtcp_mode"].asString() == "RtcpMode::kCompound"
+          ? RtcpMode::kCompound
+          : RtcpMode::kReducedSize;
+  receive_config.rtp.remb = json["rtp"]["remb"].asBool();
+  receive_config.rtp.transport_cc = json["rtp"]["transport_cc"].asBool();
+  receive_config.rtp.nack.rtp_history_ms =
+      json["rtp"]["nack"]["rtp_history_ms"].asInt64();
+  receive_config.rtp.ulpfec_payload_type =
+      json["rtp"]["ulpfec_payload_type"].asInt64();
+  receive_config.rtp.red_payload_type =
+      json["rtp"]["red_payload_type"].asInt64();
+  receive_config.rtp.rtx_ssrc = json["rtp"]["rtx_ssrc"].asInt64();
+
+  for (const auto& pl_json : json["rtp"]["rtx_payload_types"]) {
+    std::vector<std::string> members = pl_json.getMemberNames();
+    RTC_CHECK_EQ(members.size(), 1);
+    Json::Value rtx_payload_type = pl_json[members[0]];
+    receive_config.rtp.rtx_associated_payload_types[std::stoi(members[0])] =
+        rtx_payload_type.asInt64();
+  }
+  for (const auto& ext_json : json["rtp"]["extensions"]) {
+    receive_config.rtp.extensions.emplace_back(ext_json["uri"].asString(),
+                                               ext_json["id"].asInt64(),
+                                               ext_json["encrypt"].asBool());
+  }
+  return receive_config;
+}
+
+}  // namespace test.
+}  // namespace webrtc.