Start and stop RTC event logs from private extension API.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index b1be5b9616a1f3d976ac6b18292581f5f5dca6e8..641ab896ffbb7fd3390713665731bd1c9cd207f2 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -504,6 +504,10 @@ const char kEnableQuic[]                    = "enable-quic";
 // This only has an effect if QUIC protocol is enabled.
 const char kEnableQuicPortSelection[]       = "enable-quic-port-selection";
 
+// If the WebRTC logging private API is active, enables WebRTC event logging.
+const char kEnableWebRtcEventLoggingFromExtension[] =
+    "enable-webrtc-event-logging-from-extension";
+
 // Enables support for HTTP alternative services.
 const char kEnableAlternativeServices[] = "enable-alternative-services";