Strip units string in legacy perf dashboard JSON generator

tools/perf/generate_legacy_perf_dashboard_json.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
 """ Generates legacy perf dashboard json from non-telemetry based perf tests.
 Taken from chromium/build/scripts/slave/performance_log_processory.py
 (https://goo.gl/03SQRk)
 """
 
@@ skipping 121 matching lines @@
     """Processes a line that matches the standard RESULT line format.
 
     Args:
       line_match: A MatchObject as returned by re.search.
     """
     match_dict = line_match.groupdict()
     graph_name = match_dict['GRAPH'].strip()
     trace_name = match_dict['TRACE'].strip()
 
     graph = self._graphs.get(graph_name, self.Graph())
-    graph.units = match_dict['UNITS'] or ''
+    graph.units = (match_dict['UNITS'] or '').strip()
     trace = graph.traces.get(trace_name, self.Trace())
     trace.value = match_dict['VALUE']
     trace.important = match_dict['IMPORTANT'] or False
 
     # Compute the mean and standard deviation for a list or a histogram,
     # or the numerical value of a scalar value.
     if trace.value.startswith('['):
       try:
         value_list = [float(x) for x in trace.value.strip('[],').split(',')]
       except ValueError:
@@ skipping 95 matching lines @@
     digits *= 10
     exponent -= 1
   while exponent < -3:
     digits /= 10
     exponent += 1
   if digits >= 100:
     # Don't append a meaningless '.0' to an integer number.
     digits = int(digits)
   # Exponent is now divisible by 3, between -3 and 6 inclusive: (-3, 0, 3, 6).
   return '%s%s' % (digits, metric_prefixes[exponent])