Added layouttests for checking that RTCPeerConnection.onaddstream

LayoutTests/fast/mediastream/RTCPeerConnection-remotestreams-expected.txt

Index: LayoutTests/fast/mediastream/RTCPeerConnection-remotestreams-expected.txt
diff --git a/LayoutTests/fast/mediastream/RTCPeerConnection-remotestreams-expected.txt b/LayoutTests/fast/mediastream/RTCPeerConnection-remotestreams-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..9e95b3ad58ba4f565b47f70b07435926c3c0d76c
--- /dev/null
+++ b/LayoutTests/fast/mediastream/RTCPeerConnection-remotestreams-expected.txt
@@ -0,0 +1,21 @@
+Tests that an RTCPeerConnection can signal that remote streams are added and removed.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS pc.setRemoteDescription(sessionDescription, requestSucceeded1, requestFailedUnexpectedly); did not throw exception.
+PASS remote stream was added
+PASS event.stream.getVideoTracks().length is 1
+PASS event.stream.getAudioTracks().length is 1
+PASS requestSucceeded was called.
+PASS pc.getRemoteStreams().length is 1
+PASS pc.setRemoteDescription(sessionDescription, requestSucceeded2, requestFailedUnexpectedly); did not throw exception.
+PASS remote stream was removed
+PASS event.stream.getVideoTracks().length is 0
+PASS event.stream.getAudioTracks().length is 0
+PASS requestSucceeded was called.
+PASS pc.getRemoteStreams().length is 0
+PASS successfullyParsed is true
+
+TEST COMPLETE
+