Add MemoryInfra overheads to tracingMetrics

telemetry/telemetry/timeline/tracing_config.py

 # Copyright 2015 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.
 
 import re
 
 from telemetry.timeline import tracing_category_filter
 
 RECORD_MODE_PARAM = 'record_mode'
 ENABLE_SYSTRACE_PARAM = 'enable_systrace'
@@ skipping 323 matching lines @@
   """Stores the triggers for memory dumps in ChromeTraceConfig."""
   def __init__(self):
     self._triggers = []
 
   def AddTrigger(self, mode, periodic_interval_ms):
     """Adds a new trigger to config.
 
     Args:
       periodic_interval_ms: Dump time period in milliseconds.
       level_of_detail: Memory dump level of detail string.
-          Valid arguments are "light" and "detailed".
+          Valid arguments are "background", "light" and "detailed".
     """
-    assert mode in ['light', 'detailed']
+    assert mode in ['background', 'light', 'detailed']
     assert periodic_interval_ms > 0
     self._triggers.append({'mode': mode,
                            'periodic_interval_ms': periodic_interval_ms})
 
   def GetDictForChromeTracing(self):
     """Returns the dump config as dictionary for chrome tracing."""
     # An empty trigger list would mean no periodic memory dumps.
     return {'memory_dump_config': {'triggers': self._triggers}}