sandwich: Implement SandwichTaskBuilder

tools/android/loading/sandwich_metrics.py

Index: tools/android/loading/sandwich_metrics.py
diff --git a/tools/android/loading/sandwich_metrics.py b/tools/android/loading/sandwich_metrics.py
index 1a9e96d6929bcbd7526bb889ceb2175600ff6e7f..61b5815c6f02fd0e15d6bbb8a1430ff0d7227af8 100644
--- a/tools/android/loading/sandwich_metrics.py
+++ b/tools/android/loading/sandwich_metrics.py
@@ -26,20 +26,10 @@ from telemetry.util import image_util
 from telemetry.util import rgba_color
 
 import loading_trace as loading_trace_module
+import sandwich_runner
 import tracing
 
 
-# List of selected trace event categories when running chrome.
-CATEGORIES = [
-    # Need blink network trace events for prefetch_view.PrefetchSimulationView
-    'blink.net',
-
-    # Need to get mark trace events for _GetWebPageTrackedEvents()
-    'blink.user_timing',
-
-    # Need to memory dump trace event for _GetBrowserDumpEvents()
-    'disabled-by-default-memory-infra']
-
 CSV_FIELD_NAMES = [
     'id',
     'url',
@@ -247,7 +237,7 @@ def PullMetricsFromOutputDirectory(output_directory_path):
     except ValueError:
       continue
     run_path = os.path.join(output_directory_path, node_name)
-    trace_path = os.path.join(run_path, 'trace.json')
+    trace_path = os.path.join(run_path, sandwich_runner.TRACE_FILENAME)
     if not os.path.isfile(trace_path):
       continue
     logging.info('processing \'%s\'' % trace_path)
@@ -256,7 +246,7 @@ def PullMetricsFromOutputDirectory(output_directory_path):
     row_metrics.update(_PullMetricsFromLoadingTrace(loading_trace))
     row_metrics['id'] = page_id
     row_metrics['url'] = loading_trace.url
-    video_path = os.path.join(run_path, 'video.mp4')
+    video_path = os.path.join(run_path, sandwich_runner.VIDEO_FILENAME)
     if os.path.isfile(video_path):
       logging.info('processing \'%s\'' % video_path)
       completeness_record = _ExtractCompletenessRecordFromVideo(video_path)