Add Multi-tab System Health Story

tools/perf/measurements/tab_switching_unittest.py

Index: tools/perf/measurements/tab_switching_unittest.py
diff --git a/tools/perf/measurements/tab_switching_unittest.py b/tools/perf/measurements/tab_switching_unittest.py
index 79efbb116d3ace14849a694b87153d47a8cfc774..014494541c3d9a2f8ca369d0baf019fc053b1f02 100644
--- a/tools/perf/measurements/tab_switching_unittest.py
+++ b/tools/perf/measurements/tab_switching_unittest.py
@@ -65,19 +65,6 @@ class TabSwitchingUnittest(page_test_test_case.PageTestTestCase):
     expected_histogram = [
         # To get first_histogram for last tab (tab_1).
         '{"count": 0, "buckets": []}',
-        # First _IsDone check for tab_0. Retry.
-        '{"count": 0, "buckets": []}',
-        # Second _IsDone check for tab_0. Retry.
-        '{"count": 0, "buckets": []}',
-        # Third _IsDone check for tab_0. Pass.
-        '{"count": 1, "buckets": [{"low": 1, "high": 2, "count": 1}]}',
-        # To get prev_histogram. End of tab_0 loop.
-        '{"count": 1, "buckets": [{"low": 1, "high": 2, "count": 1}]}',
-        # First _IsDone check for tab_1. Retry.
-        '{"count": 1, "buckets": [{"low": 1, "high": 2, "count": 1}]}',
-        # Second _IsDone check for tab_1. Pass.
-        '{"count": 2, "buckets": [{"low": 1, "high": 2, "count": 1},'
-        '{"low": 2, "high": 3, "count": 1}]}',
         # To get prev_histogram. End of tab_1 loop.
         '{"count": 2, "buckets": [{"low": 1, "high": 2, "count": 1},'
         '{"low": 2, "high": 3, "count": 1}]}',
@@ -88,10 +75,11 @@ class TabSwitchingUnittest(page_test_test_case.PageTestTestCase):
         mock.patch('telemetry.value.histogram_util.GetHistogram',
                    mock_get_histogram),
         mock.patch('metrics.keychain_metric.KeychainMetric')):
+      measure.DidNavigateToPage(story_set.stories[0], browser.tabs[-1])
       measure.ValidateAndMeasurePage(story_set.stories[0], browser.tabs[-1],
                                      page_test_results.PageTestResults())
       self.assertEqual(len(expected_histogram),
                        len(mock_get_histogram.mock_calls))
       expected_calls = [mock.call(mock.ANY, mock.ANY, t) for t in
-                        [tab_1] + [tab_0] * 4 + [tab_1] * 3]
+                        [tab_1] + [tab_1]]
       self.assertEqual(expected_calls, mock_get_histogram.mock_calls)