Specify --test-machine-name to maps_pixel_test running on bots.

content/test/gpu/gpu_tests/cloud_storage_test_base.py

 # Copyright 2013 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.
 
 """Base classes for a test and validator which upload results
 (reference images, error images) to cloud storage."""
 
 import logging
 import os
 import re
@@ skipping 15 matching lines @@
 
 def _CompareScreenshotSamples(screenshot, expectations, device_pixel_ratio,
                               test_machine_name):
   # First scan through the expectations and see if there are any scale
   # factor overrides that would preempt the device pixel ratio. This
   # is mainly a workaround for complex tests like the Maps test.
   if test_machine_name:
     for expectation in expectations:
       if "scale_factor_overrides" in expectation:
         for override in expectation["scale_factor_overrides"]:
-          if override["machine_name"] in test_machine_name:
+          # Require exact match to avoid confusion, because some
+          # machine models and names might be subsets of others
+          # (e.g. Nexus 5 vs Nexus 5X).
+          if override["machine_name"] == test_machine_name:
             logging.warning('Overriding device_pixel_ratio ' +
                             str(device_pixel_ratio) + ' with scale factor ' +
                             str(override["scale_factor"]))
             device_pixel_ratio = override["scale_factor"]
             break
         break
   for expectation in expectations:
     if "scale_factor_overrides" in expectation:
       continue
     location = expectation["location"]
@@ skipping 231 matching lines @@
         default='')
     group.add_option('--test-machine-name',
         help='Name of the test machine. Specifying this argument causes this '
         'script to upload failure images and diffs to cloud storage directly, '
         'instead of relying on the archive_gpu_pixel_test_results.py script.',
         default='')
     group.add_option('--generated-dir',
         help='Overrides the default on-disk location for generated test images '
         '(only used for local testing without a cloud storage account)',
         default=default_generated_data_dir)