[Telemetry] AddIsEventInInteractions helper method

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

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 
 class TimelineBasedMetricException(Exception):
   """Exception that can be thrown from metrics that implements
      TimelineBasedMetric to indicate a problem arised when computing the metric.
      """
 
 
 def _TimeRangesHasOverlap(iterable_time_ranges):
   """ Returns True if there is are overlapped ranges in time ranges.
   iterable_time_ranges: an iterable of time ranges. Each time range is a
   tuple (start time, end time).
   """
   # Sort the ranges by the start time
   sorted_time_ranges = sorted(iterable_time_ranges)
   last_range = sorted_time_ranges[0]
   for current_range in sorted_time_ranges[1:]:
     start_current_range = current_range[0]
     end_last_range = last_range[1]
     if start_current_range < end_last_range:
       return True
     last_range = current_range
   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):
     """Computes metrics from a telemetry.timeline Model and a range
 
     """
     super(TimelineBasedMetric, self).__init__()
 
   def AddResults(self, model, renderer_thread, interaction_records, results):
     """Computes and adds metrics for the interaction_records' time ranges.
@@ skipping 11 matching lines @@
     """
     raise NotImplementedError()
 
   def VerifyNonOverlappedRecords(self, interaction_records):
     """This raises exceptions if interaction_records contain overlapped ranges.
     """
     if _TimeRangesHasOverlap(((r.start, r.end) for r in interaction_records)):
       raise TimelineBasedMetricException(
           'This metric does not support interaction records with overlapped '
           'time range.')