Telemetry: adds ImageDecodingBenchmarkUnitTest.

tools/perf/perf_tools/image_decoding_benchmark_unittest.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.
+
 from telemetry import multi_page_benchmark_unittest_base
-from perf_tools import loading_benchmark
+from perf_tools import image_decoding_benchmark
 
-class SmoothnessBenchmarkUnitTest(
+
+class ImageDecodingBenchmarkUnitTest(
   multi_page_benchmark_unittest_base.MultiPageBenchmarkUnitTestBase):
 
-  def testBasicFunctionality(self):
-    ps = self.CreatePageSetFromFileInUnittestDataDir('blank.html')
+  def testImageDecodingMeasurement(self):
+    ps = self.CreatePageSetFromFileInUnittestDataDir('image_decoding.html')
 
-    benchmark = loading_benchmark.LoadingBenchmark()
+    benchmark = image_decoding_benchmark.ImageDecoding()
     all_results = self.RunBenchmark(benchmark, ps)
 
     self.assertEqual(0, len(all_results.page_failures))
     self.assertEqual(1, len(all_results.page_results))
 
     results0 = all_results.page_results[0]
-    self.assertTrue(results0['Layout'].value > 0)
-    self.assertTrue(results0['Paint'].value > 0)
+    self.assertTrue('ImageDecoding_avg' in results0)
+    self.assertGreater(results0['ImageDecoding_avg'], 0)