Revert of telemetry: Remove command line args from page test

tools/perf/measurements/screenshot.py

Index: tools/perf/measurements/screenshot.py
diff --git a/tools/perf/measurements/screenshot.py b/tools/perf/measurements/screenshot.py
index 5c4345a5a4ca397ed6c1f6b6d239f2da303d9081..8564c8a473236a06435c33aaef30ee18a4521a9e 100644
--- a/tools/perf/measurements/screenshot.py
+++ b/tools/perf/measurements/screenshot.py
@@ -9,11 +9,21 @@
 
 
 class Screenshot(page_test.PageTest):
-  def __init__(self, png_outdir):
+  def __init__(self):
     super(Screenshot, self).__init__(
         action_name_to_run = 'RunPageInteractions',
         is_action_name_to_run_optional=True)
-    self._png_outdir = png_outdir
+
+  @classmethod
+  def AddCommandLineArgs(cls, parser):
+    parser.add_option('--png-outdir',
+                      help='Output directory for the PNG files')
+
+  @classmethod
+  def ProcessCommandLineArgs(cls, parser, args):
+    if not args.png_outdir:
+      parser.error('Please specify --png-outdir')
+    cls._png_outdir = args.png_outdir
 
   def ValidateAndMeasurePage(self, page, tab, results):
     if not tab.screenshot_supported: