Revert 239784 "Make page_cycler.py fully measure memory for each..."

> Make page_cycler.py fully measure memory for each page.
> 
> Telemetry makes the distinction between metrics collected for each page and for
> each page set. The fine-grained memory metrics were collected only per page set
> (although there was some histogram data collected per page).
> 
> This CL makes the memory metric module systematically report the whole data per
> page (and not only per page set) so that we can measure pages independently.
> The per page set memory metric collection is now a no-op.
> 
> BUG=323494
> 
> Review URL: https://codereview.chromium.org/91573003

TBR=pliard@chromium.org

Review URL: https://codereview.chromium.org/111773002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@239791 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/android_commands.py

@@ -25,6 +25,8 @@ import constants
 import screenshot
 import system_properties
 
+from utils import host_path_finder
+
 try:
   from pylib import pexpect
 except:
@@ -1499,6 +1501,20 @@ class AndroidCommands(object):
     logging.warning('Could not find disk IO stats.')
     return None
 
+  def PurgeUnpinnedAshmem(self):
+    """Purges the unpinned ashmem memory for the whole system.
+
+    This can be used to make memory measurements more stable in particular.
+    """
+    host_path = host_path_finder.GetMostRecentHostPath('purge_ashmem')
+    if not host_path:
+      raise Exception('Could not find the purge_ashmem binary.')
+    device_path = os.path.join(constants.TEST_EXECUTABLE_DIR, 'purge_ashmem')
+    self.PushIfNeeded(host_path, device_path)
+    if self.RunShellCommand(device_path, log_result=True):
+      return
+    raise Exception('Error while purging ashmem.')
+
   def GetMemoryUsageForPid(self, pid):
     """Returns the memory usage for given pid.