Prefer device type instead of machine name for scale factor overrides.

content/test/gpu/gpu_tests/gpu_rasterization.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.
 
 from gpu_tests import cloud_storage_test_base
 from gpu_tests import gpu_rasterization_expectations
 import page_sets
 
 from telemetry.page import page_test
 from telemetry.util import image_util
@@ skipping 43 matching lines @@
     if screenshot is None:
       raise page_test.Failure('Could not capture screenshot')
 
     device_pixel_ratio = tab.EvaluateJavaScript('window.devicePixelRatio')
     if hasattr(page, 'test_rect'):
       test_rect = [int(x * device_pixel_ratio) for x in page.test_rect]
       screenshot = image_util.Crop(screenshot, test_rect[0], test_rect[1],
                                    test_rect[2], test_rect[3])
 
     self._ValidateScreenshotSamples(
+        tab,
         page.display_name,
         screenshot,
         page.expectations,
         device_pixel_ratio)
 
 
 class GpuRasterization(cloud_storage_test_base.TestBase):
   """Tests that GPU rasterization produces valid content"""
   test = GpuRasterizationValidator
 
   def __init__(self, max_failures=None):
     super(GpuRasterization, self).__init__(max_failures=max_failures)
 
   @classmethod
   def Name(cls):
     return 'gpu_rasterization'
 
   def CreateStorySet(self, options):
     story_set = page_sets.GpuRasterizationTestsStorySet(self.GetExpectations())
     for page in story_set:
       page.script_to_evaluate_on_commit = test_harness_script
     return story_set
 
   def _CreateExpectations(self):
     return gpu_rasterization_expectations.GpuRasterizationExpectations()