Remove not-needed webrtc:: prefixes in pc/

This test drives the new tools_webrtc/remove_extra_namespace.py tool.

Bug: None
Change-Id: I9b590aa1213e4cace2d64d555f4dafd893f03606
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/327021
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41141}
diff --git a/pc/peer_connection_header_extension_unittest.cc b/pc/peer_connection_header_extension_unittest.cc
index dd5d4b0..277979b 100644
--- a/pc/peer_connection_header_extension_unittest.cc
+++ b/pc/peer_connection_header_extension_unittest.cc
@@ -114,7 +114,7 @@
         pc_factory, result.MoveValue(), std::move(observer));
   }
 
-  webrtc::test::ScopedKeyValueConfig field_trials_;
+  test::ScopedKeyValueConfig field_trials_;
   std::unique_ptr<rtc::SocketServer> socket_server_;
   rtc::AutoSocketServerThread main_thread_;
   std::vector<RtpHeaderExtensionCapability> extensions_;