Surface test times of android tests.

Right now we have no easy visibility on time taken for individual tests, since everything runs under one massive "Sharded Perf Tests" step. We're trying to balance the tests across devices to improve cycle time, so we need a way to see how long each test is actually taking.

BUG=466101

Review URL: https://codereview.chromium.org/1140783002

Cr-Commit-Position: refs/heads/master@{#329722}

build/android/pylib/perf/test_runner.py

@@ -66,11 +66,29 @@ from pylib.base import base_test_runner
 from pylib.device import device_errors
 
 
+def GetPersistedResult(test_name):
+  file_name = os.path.join(constants.PERF_OUTPUT_DIR, test_name)
+  if not os.path.exists(file_name):
+    logging.error('File not found %s', file_name)
+    return None
+
+  with file(file_name, 'r') as f:
+    return pickle.loads(f.read())
+
+
 def OutputJsonList(json_input, json_output):
   with file(json_input, 'r') as i:
     all_steps = json.load(i)
-  step_values = [{'test': k, 'device_affinity': v['device_affinity']}
-      for k, v in all_steps['steps'].iteritems()]
+
+  step_values = []
+  for k, v in all_steps['steps'].iteritems():
+    data = {'test': k, 'device_affinity': v['device_affinity']}
+
+    persisted_result = GetPersistedResult(k)
+    if persisted_result:
+      data['total_time'] = persisted_result['total_time']
+    step_values.append(data)
+
   with file(json_output, 'w') as o:
     o.write(json.dumps(step_values))
   return 0
@@ -86,13 +104,9 @@ def PrintTestOutput(test_name, json_file_name=None):
   Returns:
     exit code generated by the test step.
   """
-  file_name = os.path.join(constants.PERF_OUTPUT_DIR, test_name)
-  if not os.path.exists(file_name):
-    logging.error('File not found %s', file_name)
+  persisted_result = GetPersistedResult(test_name)
+  if not persisted_result:
     return 1
-
-  with file(file_name, 'r') as f:
-    persisted_result = pickle.loads(f.read())
   logging.info('*' * 80)
   logging.info('Output from:')
   logging.info(persisted_result['cmd'])