telemetry: add screenshot measurement

tools/perf/measurements/screenshot_unittest.py

 # Copyright 2014 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 logging
 import shutil
 import tempfile
 
-from measurements import skpicture_printer
-from telemetry import test
+from measurements import screenshot
 from telemetry.page import page_measurement_unittest_base
+from telemetry.page import page_test
 from telemetry.unittest import options_for_unittests
 
 
-class SkpicturePrinterUnitTest(
+class ScreenshotUnitTest(
       page_measurement_unittest_base.PageMeasurementUnitTestBase):
   def setUp(self):
     self._options = options_for_unittests.GetCopy()
-    self._options.skp_outdir = tempfile.mkdtemp('_skp_test')
+    self._options.png_outdir = tempfile.mkdtemp('_png_test')
 
   def tearDown(self):
-    shutil.rmtree(self._options.skp_outdir)
+    shutil.rmtree(self._options.png_outdir)
 
-  @test.Disabled('android')
-  def testSkpicturePrinter(self):
+  def testScreenshot(self):
     ps = self.CreatePageSetFromFileInUnittestDataDir('blank.html')
-    measurement = skpicture_printer.SkpicturePrinter()
-    results = self.RunMeasurement(measurement, ps, options=self._options)
-
-    # Picture printing is not supported on all platforms.
-    if results.failures:
-      assert 'not supported' in results.failures[0][1]
+    measurement = screenshot.Screenshot()
+    try:
+      results = self.RunMeasurement(measurement, ps, options=self._options)
+    except page_test.TestNotSupportedOnPlatformFailure as failure:
+      logging.warning(str(failure))
       return
 
     saved_picture_count = results.FindAllPageSpecificValuesNamed(
         'saved_picture_count')
     self.assertEquals(len(saved_picture_count), 1)
     self.assertGreater(saved_picture_count[0].GetRepresentativeNumber(), 0)