[Telemetry] Add memory and IO stats to page cycler

tools/telemetry/telemetry/core/chrome/mac_platform_backend.py

Index: tools/telemetry/telemetry/core/chrome/mac_platform_backend.py
diff --git a/tools/telemetry/telemetry/core/chrome/mac_platform_backend.py b/tools/telemetry/telemetry/core/chrome/mac_platform_backend.py
new file mode 100644
index 0000000000000000000000000000000000000000..da0dbb6c8bca918a54d560cf7aef93044ce73b1d
--- /dev/null
+++ b/tools/telemetry/telemetry/core/chrome/mac_platform_backend.py
@@ -0,0 +1,57 @@
+# Copyright (c) 2013 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.
+
+try:
+  import resource  # pylint: disable=F0401
+except ImportError:
+  resource = None  # Not available on all platforms
+import subprocess
+
+from telemetry.core.chrome import platform_backend
+
+
+class MacPlatformBackend(platform_backend.PlatformBackend):
+  # pylint: disable=W0613
+  def StartRawDisplayFrameRateMeasurement(self, trace_tag):
+    raise NotImplementedError()
+
+  def StopRawDisplayFrameRateMeasurement(self):
+    raise NotImplementedError()
+
+  def IsThermallyThrottled(self):
+    raise NotImplementedError()
+
+  def HasBeenThermallyThrottled(self):
+    raise NotImplementedError()
+
+  def GetSystemCommitCharge(self):
+    vm_stat = subprocess.Popen(['vm_stat'],
+                               stdout=subprocess.PIPE).communicate()[0]
+    for stat in vm_stat.splitlines():
+      key_value = stat.split(':')
+      if key_value[0] == 'Pages active':
+        pages_active = int(key_value[1].strip()[:-1])  # Strip trailing '.'
+        return pages_active * resource.getpagesize() / 1024
+    return 0
+
+  def GetMemoryStats(self, pid):
+    pid_rss_vsz_list = subprocess.Popen(['ps', '-e', '-o', 'pid=,rss=,vsz='],
+                                        stdout=subprocess.PIPE).communicate()[0]
+    for pid_rss_vsz in pid_rss_vsz_list.splitlines():
+      pid_rss_vsz = pid_rss_vsz.split()
+      if int(pid_rss_vsz[0]) == pid:
+        return {'VM': int(pid_rss_vsz[2].strip()),
+                'WorkingSetSize': int(pid_rss_vsz[1].strip())}
+    return {}
+
+  def GetChildPids(self, pid):
+    """Retunds a list of child pids of |pid|."""
+    child_pids = []
+    pid_ppid_list = subprocess.Popen(['ps', '-e', '-o', 'pid=', '-o', 'ppid='],
+                                     stdout=subprocess.PIPE).communicate()[0]
+    for pid_ppid in pid_ppid_list.splitlines():
+      pid_ppid = pid_ppid.split()
+      if int(pid_ppid[1].strip()) == pid:
+        child_pids.append(int(pid_ppid[0].strip()))
+    return child_pids