Do not add TTI if interactive state was not reached

tracing/tracing/metrics/system_health/loading_metric.html

Index: tracing/tracing/metrics/system_health/loading_metric.html
diff --git a/tracing/tracing/metrics/system_health/loading_metric.html b/tracing/tracing/metrics/system_health/loading_metric.html
index 08966b87854abdbeac0a0dc374f6a7f85425109e..1450304bf1940f1fe8bf7435347387785b9f584d 100644
--- a/tracing/tracing/metrics/system_health/loading_metric.html
+++ b/tracing/tracing/metrics/system_health/loading_metric.html
@@ -266,6 +266,12 @@ tr.exportTo('tr.metrics.sh', function() {
     for (var ev of[...rendererHelper.mainThread.sliceGroup.childEvents()]) {
       if (ev.start < firstInteractiveCandidate)
         continue;
+      if (hasCategoryAndName(ev, 'blink.user_timing', 'navigationStart')) {
+        // We have a new navigation before we could find our interactive window
+        // Cannot find TTI for current navigation
+        return;
+      }
+
       var interactiveDurationSoFar = ev.start - firstInteractiveCandidate;
       if (interactiveDurationSoFar >= INTERACTIVE_WINDOW_SIZE) {
         firstInteractive = firstInteractiveCandidate;
@@ -273,7 +279,8 @@ tr.exportTo('tr.metrics.sh', function() {
       }
       if (ev.title === 'TaskQueueManager::ProcessTaskFromWorkQueue' &&
           ev.duration > RESPONSIVENESS_THRESHOLD) {
-        firstInteractiveCandidate = ev.end - 50;
+        firstInteractiveCandidate = ev.end - RESPONSIVENESS_THRESHOLD;
+
       }
     }
     var diagnosticDict = rendererHelper.generateTimeBreakdownTree(