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

tools/telemetry/telemetry/value/scalar.py

Index: tools/telemetry/telemetry/value/scalar.py
diff --git a/tools/telemetry/telemetry/value/scalar.py b/tools/telemetry/telemetry/value/scalar.py
index d83753af414e27ab98aa576ee823413b400d728f..d0c196e0832746f9bba88fd0c838a49788488774 100644
--- a/tools/telemetry/telemetry/value/scalar.py
+++ b/tools/telemetry/telemetry/value/scalar.py
@@ -11,14 +11,15 @@ from telemetry.value import none_values
 
 class ScalarValue(value_module.Value):
   def __init__(self, page, name, units, value, important=True,
-               description=None, none_value_reason=None):
+               description=None, none_value_reason=None, paths=None):
     """A single value (float or integer) result from a test.
 
     A test that counts the number of DOM elements in a page might produce a
     scalar value:
        ScalarValue(page, 'num_dom_elements', 'count', num_elements)
     """
-    super(ScalarValue, self).__init__(page, name, units, important, description)
+    super(ScalarValue, self).__init__(page, name, units, important, description,
+                                      paths)
     assert value is None or isinstance(value, numbers.Number)
     none_values.ValidateNoneValueReason(value, none_value_reason)
     self.value = value
@@ -29,13 +30,15 @@ class ScalarValue(value_module.Value):
       page_name = self.page.url
     else:
       page_name = None
-    return 'ScalarValue(%s, %s, %s, %s, important=%s, description=%s)' % (
+    return ('ScalarValue(%s, %s, %s, %s, important=%s, description=%s, '
+           'paths=%s)') % (
       page_name,
       self.name,
       self.units,
       self.value,
       self.important,
-      self.description)
+      self.description,
+      self.paths)
 
   def GetBuildbotDataType(self, output_context):
     if self._IsImportantGivenOutputIntent(output_context):