Test closing multiple datachannels

Tests that when a PeerConnection closes, all open datachannels
get the error and close events.
(The bug was fixed earlier, but this adds a test for it)

Bug: webrtc:6881
Change-Id: I4734f3d29333dcad98c34cf5dbdc8d4b04a5f986
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2568278
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833346}

third_party/blink/web_tests/external/wpt/webrtc/RTCDataChannel-close.html

@@ -45,7 +45,7 @@ for (const options of [{}, {negotiated: true, id: 0}]) {
     assert_true(closingSeen, 'Closing event was seen');
   }, `Close ${mode} causes closing and close event to be called`);
 
-  promise_test(async t => {
+   promise_test(async t => {
     const pc1 = new RTCPeerConnection();
     t.add_cleanup(() => pc1.close());
     const [channel1, channel2] = await createDataChannelPair(t, options, pc1);
@@ -100,5 +100,81 @@ for (const options of [{}, {negotiated: true, id: 0}]) {
     pc1.close();
     await new Promise(resolve => t.step_timeout(resolve, 10));
   }, `Close peerconnection after ${mode} close causes no events`);
+
+  promise_test(async t => {
+    const pc1 = new RTCPeerConnection();
+    t.add_cleanup(() => pc1.close());
+    const pc2 = new RTCPeerConnection();
+    t.add_cleanup(() => pc2.close());
+    pc1.createDataChannel('not-counted', options);
+    const tokenDataChannel = new Promise(resolve => {
+      pc2.ondatachannel = resolve;
+    });
+    exchangeIceCandidates(pc1, pc2);
+    await exchangeOfferAnswer(pc1, pc2);
+    if (!options.negotiated) {
+      await tokenDataChannel;
+    }
+    let closeExpectedCount = 0;
+    let errorExpectedCount = 0;
+    let resolveCountIsZero;
+    let waitForCountIsZero = new Promise(resolve => {
+      resolveCountIsZero = resolve;
+    });
+    for (let i = 1; i <= 10; i++) {
+      if ('id' in options) {
+        options.id = i;
+      }
+      pc1.createDataChannel('', options);
+      if (options.negotiated) {
+        const channel = pc2.createDataChannel('', options);
+        channel.addEventListener('error', t.step_func(event => {
+          assert_true(event instanceof RTCErrorEvent, 'error event ' + event);
+          errorExpectedCount -= 1;
+        }));
+        channel.addEventListener('close', t.step_func(event => {
+          closeExpectedCount -= 1;
+          if (closeExpectedCount == 0) {
+            resolveCountIsZero();
+          }
+        }));
+      } else {
+        await new Promise(resolve => {
+          pc2.ondatachannel = ({channel}) => {
+            channel.addEventListener('error', t.step_func(event => {
+              assert_true(event instanceof RTCErrorEvent);
+              errorExpectedCount -= 1;
+            }));
+            channel.addEventListener('close', t.step_func(event => {
+              closeExpectedCount -= 1;
+              if (closeExpectedCount == 0) {
+                resolveCountIsZero();
+              }
+            }));
+            resolve();
+          }
+        });
+      }
+      ++closeExpectedCount;
+      ++errorExpectedCount;
+    }
+    assert_equals(closeExpectedCount, 10);
+    // We have to wait until SCTP is connected before we close, otherwise
+    // there will be no signal.
+    // The state is not available under Plan B, and unreliable on negotiated
+    // channels.
+    // TODO(bugs.webrtc.org/12259): Remove dependency on "negotiated"
+    if (pc1.sctp && !options.negotiated) {
+      waitForState(pc1.sctp, 'connected');
+    } else {
+      // Under plan B, we don't have a dtls transport to wait on, so just
+      // wait a bit.
+      await new Promise(resolve => t.step_timeout(resolve, 100));
+    }
+    pc1.close();
+    await waitForCountIsZero;
+    assert_equals(closeExpectedCount, 0);
+    assert_equals(errorExpectedCount, 0);
+  }, `Close peerconnection causes close event and error on many channels, ${mode}`);
 }
 </script>