Refactor BenchmarkResult.Add to take enum for data_type

tools/telemetry/telemetry/page/html_page_measurement_results.py

Index: tools/telemetry/telemetry/page/html_page_measurement_results.py
===================================================================
--- tools/telemetry/telemetry/page/html_page_measurement_results.py	(revision 217866)
+++ tools/telemetry/telemetry/page/html_page_measurement_results.py	(working copy)
@@ -11,6 +11,7 @@
 
 from telemetry.core import util
 from telemetry.page import buildbot_page_measurement_results
+from telemetry.page import result_data_type
 
 # Get build/util scripts into our path.
 sys.path.append(os.path.abspath(os.path.join(
@@ -82,7 +83,7 @@
     self._output_stream.truncate()
 
   def _PrintPerfResult(self, measurement, trace, values, units,
-                       result_type='default'):
+                       result_type=result_data_type.DEFAULT):
     super(HtmlPageMeasurementResults, self)._PrintPerfResult(
         measurement, trace, values, units, result_type)
 
@@ -94,7 +95,7 @@
     self._result_json['tests'][self._test_name]['metrics'][metric_name] = {
         'current': values,
         'units': units,
-        'important': result_type == 'default'
+        'important': result_type == result_data_type.DEFAULT
         }
 
   def PrintSummary(self):