Adding a test for measuring memory usage.

tools/perf/perf_tools/memory_benchmark.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
+
+MEMORY_HISTOGRAMS = [
+    {'name': 'V8.MemoryExternalFragmentationTotal', 'units': 'percent'},
+    {'name': 'V8.MemoryHeapSampleTotalCommitted', 'units': 'kb'},
+    {'name': 'V8.MemoryHeapSampleTotalUsed', 'units': 'kb'}]
+
+class MemoryBenchmark(multi_page_benchmark.MultiPageBenchmark):
+  def __init__(self):
+    super(MemoryBenchmark, self).__init__('stress_memory')
+
+  def CustomizeBrowserOptions(self, options):
+    options.AppendExtraBrowserArg('--dom-automation')
+
+  def CanRunForPage(self, page):
+    return hasattr(page, 'stress_memory')
+
+  def MeasurePage(self, page, tab, results):
+    for histogram in MEMORY_HISTOGRAMS:
+      name = histogram['name']
+      data = tab.runtime.Evaluate(
+          'window.domAutomationController.getHistogram("%s")' % name)
+      results.Add(name, histogram['units'], data, data_type='histogram')