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

tools/telemetry/telemetry/value/list_of_string_values.py

Index: tools/telemetry/telemetry/value/list_of_string_values.py
diff --git a/tools/telemetry/telemetry/value/list_of_string_values.py b/tools/telemetry/telemetry/value/list_of_string_values.py
index 4f3604a44f3300ea3dce0cd05ee29ae2504fe83e..0de21292c04542ec0a03a9a9bdd1e4190a7efebe 100644
--- a/tools/telemetry/telemetry/value/list_of_string_values.py
+++ b/tools/telemetry/telemetry/value/list_of_string_values.py
@@ -9,9 +9,9 @@ from telemetry.value import none_values
 class ListOfStringValues(value_module.Value):
   def __init__(self, page, name, units, values,
                important=True, description=None, none_value_reason=None,
-               same_page_merge_policy=value_module.CONCATENATE):
+               same_page_merge_policy=value_module.CONCATENATE, paths=None):
     super(ListOfStringValues, self).__init__(page, name, units, important,
-                                             description)
+                                             description, paths)
     if values is not None:
       assert isinstance(values, list)
       assert len(values) > 0
@@ -30,15 +30,17 @@ class ListOfStringValues(value_module.Value):
       merge_policy = 'CONCATENATE'
     else:
       merge_policy = 'PICK_FIRST'
-    return ('ListOfStringValues(%s, %s, %s, %s, ' +
-            'important=%s, description=%s, same_page_merge_policy=%s)') % (
+    return ('ListOfStringValues(%s, %s, %s, %s, '
+            'important=%s, description=%s, same_page_merge_policy=%s, '
+            'paths=%s)') % (
               page_name,
               self.name,
               self.units,
               repr(self.values),
               self.important,
               self.description,
-              merge_policy)
+              merge_policy,
+              self.paths)
 
   def GetBuildbotDataType(self, output_context):
     if self._IsImportantGivenOutputIntent(output_context):