[Telemetry] Add capability for values to reference external files.

tools/telemetry/telemetry/value/histogram.py

 # Copyright 2013 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 json
 
 from telemetry import value as value_module
 from telemetry import perf_tests_helper
 
 
 class HistogramValueBucket(object):
@@ skipping 11 matching lines @@
 
   def ToJSONString(self):
     return '{%s}' % ', '.join([
       '"low": %i' % self.low,
       '"high": %i' % self.high,
       '"count": %i' % self.count])
 
 class HistogramValue(value_module.Value):
   def __init__(self, page, name, units,
                raw_value=None, raw_value_json=None, important=True,
-               description=None):
+               description=None, paths=None):
     super(HistogramValue, self).__init__(page, name, units, important,
-                                         description)
+                                         description, paths)
     if raw_value_json:
       assert raw_value == None, \
              'Don\'t specify both raw_value and raw_value_json'
       raw_value = json.loads(raw_value_json)
     if raw_value:
       assert 'buckets' in raw_value
       assert isinstance(raw_value['buckets'], list)
       self.buckets = []
       for bucket in raw_value['buckets']:
         self.buckets.append(HistogramValueBucket(
           low=bucket['low'],
           high=bucket['high'],
           count=bucket['count']))
     else:
       self.buckets = []
 
   def __repr__(self):
     if self.page:
       page_name = self.page.url
     else:
       page_name = None
     return ('HistogramValue(%s, %s, %s, raw_json_string="%s", '
-            'important=%s, description=%s') % (
+            'important=%s, description=%s, paths=%s') % (
               page_name,
               self.name, self.units,
               self.ToJSONString(),
               self.important,
-              self.description)
+              self.description,
+              self.paths)
 
   def GetBuildbotDataType(self, output_context):
     if self._IsImportantGivenOutputIntent(output_context):
       return 'histogram'
     return 'unimportant-histogram'
 
   def GetBuildbotValue(self):
     # More buildbot insanity: perf_tests_results_helper requires the histogram
     # to be an array of size one.
     return [self.ToJSONString()]
@@ skipping 44 matching lines @@
         important=v0.important)
 
   @classmethod
   def MergeLikeValuesFromDifferentPages(cls, values,
                                         group_by_name_suffix=False):
     # Histograms cannot be merged across pages, at least for now. It should be
     # theoretically possible, just requires more work. Instead, return None.
     # This signals to the merging code that the data is unmergable and it will
     # cope accordingly.
     return None