Switch example peerconnection server to ABSL_FLAG.

TBR=kwiberg@webrtc.org

Bug: webrtc:10616
Change-Id: I611f6f67c5473b7f7ef623fa788e5403e7a8001a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/143790
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28373}

3 files changed, 17 insertions, 18 deletions

diff --git a/examples/BUILD.gn b/examples/BUILD.gn
index eed92229cc..fdff31a5c9 100644
--- a/examples/BUILD.gn
+++ b/examples/BUILD.gn
@@ -727,6 +727,8 @@ if (is_linux || is_win) {
       "../rtc_tools:command_line_parser",
       "../system_wrappers:field_trial",
       "../test:field_trial",
+      "//third_party/abseil-cpp/absl/flags:flag",
+      "//third_party/abseil-cpp/absl/flags:parse",
     ]
   }
   rtc_executable("relayserver") {
diff --git a/examples/DEPS b/examples/DEPS
index 114cda384b..1604a6a513 100644
--- a/examples/DEPS
+++ b/examples/DEPS
@@ -10,4 +10,7 @@ include_rules = [
   "+sdk/objc",
   "+system_wrappers/include",
   "+third_party/libyuv",
+
+  # Abseil flags are allowed in tests and tools.
+  "+absl/flags",
 ]
diff --git a/examples/peerconnection/server/main.cc b/examples/peerconnection/server/main.cc
index 79b2c2ce3b..9be7685660 100644
--- a/examples/peerconnection/server/main.cc
+++ b/examples/peerconnection/server/main.cc
@@ -19,14 +19,15 @@
 #include <string>
 #include <vector>
 
+#include "absl/flags/flag.h"
+#include "absl/flags/parse.h"
 #include "examples/peerconnection/server/data_socket.h"
 #include "examples/peerconnection/server/peer_channel.h"
-#include "rtc_base/flags.h"
-#include "rtc_tools/simple_command_line_parser.h"
 #include "system_wrappers/include/field_trial.h"
 #include "test/field_trial.h"
 
-WEBRTC_DEFINE_string(
+ABSL_FLAG(
+    std::string,
     force_fieldtrials,
     "",
     "Field trials control experimental features. This flag specifies the field "
@@ -34,6 +35,7 @@ WEBRTC_DEFINE_string(
     "--force_fieldtrials=WebRTC-FooFeature/Enabled/ "
     "will assign the group Enabled to field trial WebRTC-FooFeature. Multiple "
     "trials are separated by \"/\"");
+ABSL_FLAG(int, port, 8888, "default: 8888");
 
 static const size_t kMaxConnections = (FD_SETSIZE - 2);
 
@@ -63,25 +65,17 @@ void HandleBrowserRequest(DataSocket* ds, bool* quit) {
 }
 
 int main(int argc, char* argv[]) {
-  std::string program_name = argv[0];
-  std::string usage = "Example usage: " + program_name + " --port=8888";
-  webrtc::test::CommandLineParser parser;
-  parser.Init(argc, argv);
-  parser.SetUsageMessage(usage);
-  parser.SetFlag("port", "8888");
-  parser.SetFlag("help", "false");
-  parser.ProcessFlags();
-
-  if (parser.GetFlag("help") == "true") {
-    parser.PrintUsageMessage();
-    return 0;
-  }
+  absl::ParseCommandLine(argc, argv);
+  // TODO(bugs.webrtc.org/10616): Add program usage message when Abseil
+  // flags supports it.
+  // std::string usage = "Example usage: " + program_name + " --port=8888";
 
   // InitFieldTrialsFromString stores the char*, so the char array must outlive
   // the application.
-  webrtc::field_trial::InitFieldTrialsFromString(FLAG_force_fieldtrials);
+  webrtc::field_trial::InitFieldTrialsFromString(
+      absl::GetFlag(FLAGS_force_fieldtrials).c_str());
 
-  int port = strtol((parser.GetFlag("port")).c_str(), NULL, 10);
+  int port = absl::GetFlag(FLAGS_port);
 
   // Abort if the user specifies a port that is outside the allowed
   // range [1, 65535].