RTCRtpReceiver.getContributingSources() added.

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

Index: third_party/WebKit/Source/modules/peerconnection/RTCRtpContributingSource.idl
diff --git a/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.idl b/third_party/WebKit/Source/modules/peerconnection/RTCRtpContributingSource.idl
similarity index 54%
copy from third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.idl
copy to third_party/WebKit/Source/modules/peerconnection/RTCRtpContributingSource.idl
index c94a2889014d2ba60c65980f710d0b30e6984034..3c0f1e3953ce9ab65861fcab118bd9b0a5bcc854 100644
--- a/third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.idl
+++ b/third_party/WebKit/Source/modules/peerconnection/RTCRtpContributingSource.idl
@@ -2,11 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// https://w3c.github.io/webrtc-pc/#rtcrtpreceiver-interface
+// https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource
 [
     RuntimeEnabled=RTCRtpReceiver,
-] interface RTCRtpReceiver {
-    readonly attribute MediaStreamTrack track;
+] interface RTCRtpContributingSource {
+    readonly attribute DOMHighResTimeStamp timestamp;
+    readonly attribute unsigned long       source;
 
-    // TODO(hbos): Support every member of the spec. https://crbug.com/700916
+    // TODO(hbos): Support every member of the spec. https://crbug.com/705993
 };