Add a TBMv2 webrtc_rendering_metric.

tracing/tracing/base/utils_test.html

Index: tracing/tracing/base/utils_test.html
diff --git a/tracing/tracing/base/utils_test.html b/tracing/tracing/base/utils_test.html
index 8e7c91a7fceb57231f766e86c90dc45b4e7ccc64..5f8ff665169f7036c6657e7520c40b20c055157a 100644
--- a/tracing/tracing/base/utils_test.html
+++ b/tracing/tracing/base/utils_test.html
@@ -29,5 +29,21 @@ tr.b.unittest.testSuite(function() {
   test('formatDate', function() {
     assert.strictEqual(tr.b.formatDate(new Date(0)), '1970-01-01 00:00:00');
   });
+
+  test('runLengthEncoding', function() {
+    assert.deepEqual(tr.b.runLengthEncoding([]), []);
+
+    var encoded = tr.b.runLengthEncoding([1, 1]);
+    assert.deepEqual(encoded.map(x => x.value), [1]);
+    assert.deepEqual(encoded.map(x => x.count), [2]);
+
+    encoded = tr.b.runLengthEncoding([1, 2]);
+    assert.deepEqual(encoded.map(x => x.value), [1, 2]);
+    assert.deepEqual(encoded.map(x => x.count), [1, 1]);
+
+    encoded = tr.b.runLengthEncoding([1, 1, 2, 2, 2, 3, 1, 1]);
+    assert.deepEqual(encoded.map(x => x.value), [1, 2, 3, 1]);
+    assert.deepEqual(encoded.map(x => x.count), [2, 3, 1, 2]);
+  });
 });
 </script>