Update skpicture_printer to use results.AddValue(...)

tools/perf/measurements/skpicture_printer.py

 # Copyright 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 import glob
 import os
 
 from telemetry.page import page_measurement
+from telemetry.value import scalar
 
 
 _JS = 'chrome.gpuBenchmarking.printToSkPicture("{0}");'
 
 
 class SkpicturePrinter(page_measurement.PageMeasurement):
   @classmethod
   def AddCommandLineArgs(cls, parser):
     parser.add_option('-s', '--skp-outdir',
                       help='Output directory for the SKP files')
@@ skipping 13 matching lines @@
     if tab.browser.platform.GetOSName() in ['android', 'chromeos']:
       raise page_measurement.MeasurementFailure(
           'SkPicture printing not supported on this platform')
 
     # Replace win32 path separator char '\' with '\\'.
     outpath = os.path.abspath(
         os.path.join(self._skp_outdir, page.file_safe_name))
     js = _JS.format(outpath.replace('\\', '\\\\'))
     tab.EvaluateJavaScript(js)
     pictures = glob.glob(os.path.join(outpath, '*.skp'))
-    results.Add('saved_picture_count', 'count', len(pictures))
+    results.AddValue(scalar.ScalarValue(
+        results.current_page, 'saved_picture_count', 'count', len(pictures)))