WebRTC perfetto chromium integration

Bug: webrtc:15917
Change-Id: I2a459565364e0eedba8d22c23427409b35ba8387
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/348780
Reviewed-by: Mikhail Khokhlov <khokhlov@google.com>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@google.com>
Cr-Commit-Position: refs/heads/main@{#42192}
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
index 219de19..33a5355 100644
--- a/build_overrides/build.gni
+++ b/build_overrides/build.gni
@@ -55,6 +55,8 @@
   # purposes. In any case, it doesn't depend on //third_party/perfetto which
   # is used for base tracing, so this feature is disabled.
   enable_base_tracing = false
+
+  # TODO(b/336718643): Remove use_perfetto_client_library_flag.
   use_perfetto_client_library = false
   use_perfetto_trace_processor = false
 
diff --git a/webrtc.gni b/webrtc.gni
index de35c21..f7a8e73 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -388,6 +388,12 @@
     rtc_common_configs += [ "//build/config/compiler:enable_arc" ]
   }
 }
+
+# TODO(b/336718643): Remove use_perfetto_client_library_flag.
+if (build_with_chromium && use_perfetto_client_library) {
+  rtc_use_perfetto = true
+}
+
 if (rtc_use_perfetto) {
   rtc_common_configs += [ "//third_party/perfetto/gn:public_config" ]
 }