Expose the chromium waterfall in sheriff-o-matic.

Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html

Index: Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html
diff --git a/Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html b/Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html
index c4119bbc9bf5d09693f45140cbee0b002d32d757..93d7e0e78845366ce66cdecdda482dbe5800298d 100644
--- a/Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html
+++ b/Tools/GardeningServer/ui/ct-embedded-flakiness-dashboard-tests.html
@@ -18,18 +18,20 @@ asyncTest("url", 1, function() {
   }
 
   try {
-    ui.urlForEmbeddedFlakinessDashboard = function(test, step) { return "about:blank#" + test + step; }
+    ui.urlForEmbeddedFlakinessDashboard = function(test, step, tree) { return "about:blank#" + test + step + tree; }
     var embeddedFlakinessDashboard = document.createElement('ct-embedded-flakiness-dashboard');
     var testName = "foo/bar.html";
     var step = "foo_tests";
+    var tree = "blink";
     embeddedFlakinessDashboard.test = {
       testName: testName,
       step: step,
     };
+    embeddedFlakinessDashboard.tree = tree;
 
     requestAnimationFrame(function() {
       var iframe = embeddedFlakinessDashboard.shadowRoot.querySelector('#iframe');
-      equal(iframe.src, ui.urlForEmbeddedFlakinessDashboard(testName, step));
+      equal(iframe.src, ui.urlForEmbeddedFlakinessDashboard(testName, step, tree));
       reset();
       start();
     });
@@ -55,4 +57,4 @@ asyncTest("heightChanged", 1, function() {
 });
 
 })()
-</script>
+</script>