Support value lists in CSV outputter

telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py

Index: telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py
diff --git a/telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py b/telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py
index 43fb9738be93a7c747300f9dcaf53950f9f28256..65442e7a92cb81299690749385716a3f42f9b6f7 100644
--- a/telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py
+++ b/telemetry/telemetry/internal/results/csv_pivot_table_output_formatter.py
@@ -5,6 +5,7 @@
 import csv
 
 from telemetry.internal.results import output_formatter
+from telemetry.value import list_of_scalar_values
 from telemetry.value import scalar
 from telemetry.value import trace
 
@@ -22,7 +23,7 @@ class CsvPivotTableOutputFormatter(output_formatter.OutputFormatter):
   If the trace_tag contains a comma, it will be written as several
   comma-separated values.
 
-  This class only processes scalar values.
+  This class only processes scalar values and lists of scalar values.
   """
 
   FIELDS = ['story_set', 'page', 'name', 'value', 'units', 'run_index']
@@ -51,11 +52,16 @@ class CsvPivotTableOutputFormatter(output_formatter.OutputFormatter):
           'run_index': run_index,
       }
       for value in run.values:
+        val_string = None
         if (isinstance(value, scalar.ScalarValue) or
             isinstance(value, trace.TraceValue)):
+            val_string = str(value.value)
+        elif isinstance(value, list_of_scalar_values.ListOfScalarValues):
+            val_string = ' '.join(str(v) for v in value.values)
+        if val_string:
           value_dict = {
             'name': value.name,
-            'value': value.value,
+            'value': val_string,
             'units': value.units,
           }
           value_dict.update(page_dict.items())