[Telemetry] Add an example for adding an end to end Telemetry benchmark

tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py

Index: tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py
diff --git a/tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py b/tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py
index f406b12c1403169a175c9b550506c219cb5c6f00..71f3f15ad4e34d1fcb3e71c57af00e24306d339d 100644
--- a/tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py
+++ b/tools/telemetry/telemetry/web_perf/metrics/timeline_based_metric.py
@@ -26,6 +26,23 @@ def _TimeRangesHasOverlap(iterable_time_ranges):
   return False
 
 
+def IsEventInInteractions(event, interaction_records):
+  """ Return True if event is in any of the interaction records' time range.
+
+  Args:
+    event: an instance of telemetry.timeline.event.TimelineEvent.
+    interaction_records: a list of interaction records, whereas each record is
+      an instance of
+      telemetry.web_perf.timeline_interaction_record.TimelineInteractionRecord.
+
+  Returns:
+    True if |event|'s start & end time is in any of the |interaction_records|'s
+    time range.
+  """
+  return any(ir.start <= event.start and ir.end >= event.end for ir
+             in interaction_records)
+
+
 class TimelineBasedMetric(object):
 
   def __init__(self):