Promise-based RTCPeerConnection::getStats implementation.

third_party/WebKit/Source/modules/peerconnection/RTCStatsReport.idl

Index: third_party/WebKit/Source/modules/peerconnection/RTCStatsReport.idl
diff --git a/content/test/data/service_worker/fetch_event_respond_with_fetch.js b/third_party/WebKit/Source/modules/peerconnection/RTCStatsReport.idl
similarity index 57%
copy from content/test/data/service_worker/fetch_event_respond_with_fetch.js
copy to third_party/WebKit/Source/modules/peerconnection/RTCStatsReport.idl
index df76d0a094fd0d876c78cc9f327df6e213e056c2..3b9f98a730f9c9223d43bfd5e2f3d861c1feecda 100644
--- a/content/test/data/service_worker/fetch_event_respond_with_fetch.js
+++ b/third_party/WebKit/Source/modules/peerconnection/RTCStatsReport.idl
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-this.onfetch = function(event) {
-  event.respondWith(fetch(event.request));
+// https://w3c.github.io/webrtc-pc/#rtcstatsreport-object
+interface RTCStatsReport {
+    readonly maplike<DOMString, object>;
 };