Add scrolling power test.

tools/perf/benchmarks/power.py

Index: tools/perf/benchmarks/power.py
diff --git a/tools/perf/benchmarks/power.py b/tools/perf/benchmarks/power.py
index 9061ee1b490aae6b641e0e458ba42a6741960667..3e49005f1b05ba33e7a258a9afdd24c72df87bd8 100644
--- a/tools/perf/benchmarks/power.py
+++ b/tools/perf/benchmarks/power.py
@@ -178,3 +178,14 @@ class PowerGpuRasterizationTop25(perf_benchmark.PerfBenchmark):
     if found:
       stories.RemoveStory(found)
     return stories
+
+
+@benchmark.Enabled('mac')
+class PowerScrollingTrivialPage(perf_benchmark.PerfBenchmark):
+  """Scroll a trivial page and measure power consumption."""
+  test = power.QuiescentPower
+  page_set = page_sets.TrivialScrollStorySet
+
+  @classmethod
+  def Name(cls):
+    return 'power.trivial_scroll'