telemetry: handle tests that are not supported on a platform.

tools/perf/measurements/rasterize_and_record.py

 # Copyright (c) 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 logging
 import time
 
 from metrics import rendering_stats
 from telemetry.page import page_measurement
+from telemetry.page import page_test
 from telemetry.page.perf_tests_helper import FlattenList
 import telemetry.core.timeline.bounds as timeline_bounds
 from telemetry.core.timeline.model import TimelineModel
 from telemetry.core.timeline.model import MarkerMismatchError
 from telemetry.core.timeline.model import MarkerOverlapError
 
 TIMELINE_MARKER = 'RasterizeAndRecord'
 
 
 class RasterizeAndRecord(page_measurement.PageMeasurement):
@@ skipping 34 matching lines @@
 
   def DidStartBrowser(self, browser):
     # Check if the we actually have threaded forced compositing enabled.
     system_info = browser.GetSystemInfo()
     if (system_info.gpu.feature_status
         and system_info.gpu.feature_status.get(
             'compositing', None) == 'enabled_force_threaded'):
       self._compositing_features_enabled = True
 
   def MeasurePage(self, page, tab, results):
+    # Throw and exception if threaded forced compositing is not enabled.

[tonyg, 2014/03/14 01:32:49]

s/and/an/

Or actually, just delete the comment altogether. It doesn't add much value.

[ernstm, 2014/03/24 22:27:22]

Done.

     if not self._compositing_features_enabled:
-      logging.warning('Warning: compositing feature status unknown or not '+
-                      'forced and threaded. Skipping measurement.')
-      return
+      raise page_test.TestNotSupportedOnPlatformFailure(
+          'Compositing feature status unknown or not '+
+          'forced and threaded. Skipping measurement.')
 
     # Rasterize only what's visible.
     tab.ExecuteJavaScript(
         'chrome.gpuBenchmarking.setRasterizeOnlyVisibleContent();')
 
     # Wait until the page has loaded and come to a somewhat steady state.
     # Needs to be adjusted for every device (~2 seconds for workstation).
     time.sleep(float(self.options.start_wait_time))
 
     # Render one frame before we start gathering a trace. On some pages, the
@@ skipping 36 matching lines @@
 
     stats = rendering_stats.RenderingStats(
         renderer_process, timeline.browser_process, timeline_ranges)
 
     results.Add('rasterize_time', 'ms', max(FlattenList(stats.rasterize_times)))
     results.Add('record_time', 'ms', max(FlattenList(stats.record_times)))
     results.Add('rasterized_pixels', 'pixels',
                 max(FlattenList(stats.rasterized_pixel_counts)))
     results.Add('recorded_pixels', 'pixels',
                 max(FlattenList(stats.recorded_pixel_counts)))