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

tools/perf/measurements/rasterize_and_record.py

Index: tools/perf/measurements/rasterize_and_record.py
diff --git a/tools/perf/measurements/rasterize_and_record.py b/tools/perf/measurements/rasterize_and_record.py
index 5e4bd75e2536edfa231be664ba21f8cf1cf96a33..07411edc83038209d4c3de2faeb8727c7e19482c 100644
--- a/tools/perf/measurements/rasterize_and_record.py
+++ b/tools/perf/measurements/rasterize_and_record.py
@@ -2,11 +2,11 @@
 # 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
@@ -61,10 +61,11 @@ class RasterizeAndRecord(page_measurement.PageMeasurement):
       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(