Reland: Track memory consumption of SP on top 7 sites

This is a reland of the memory perf test.

R=chrishtr
BUG=474768

Review URL: https://codereview.chromium.org/1066223002

Cr-Commit-Position: refs/heads/master@{#324307}

tools/perf/benchmarks/memory.py

@@ -26,3 +26,18 @@ class MemoryTop7Stress(benchmark.Benchmark):
   @classmethod
   def Name(cls):
     return 'memory.top_7_stress'
+
+
+class MemoryTop7StressWithSlimmingPaint(benchmark.Benchmark):
+  """Use (recorded) real world web sites and measure memory consumption,
+  with --enable--slimming-paint."""
+
+  test = memory.Memory
+  page_set = page_sets.Top7StressPageSet
+
+  def CustomizeBrowserOptions(self, options):
+    options.AppendExtraBrowserArgs(['--enable-slimming-paint'])
+
+  @classmethod
+  def Name(cls):
+    return 'memory.top_7_stress_slimming_paint'