Take screenshots using /system/bin/screencap instead of monkeyrunner.

build/android/pylib/android_commands.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.
 
 """Provides an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 
 import collections
@@ skipping 1048 matching lines @@
 
       status = self._adb.SendShellCommand(
           '\'ls "%s" >/dev/null 2>&1; echo $?\'' % (file_name))
       return int(status) == 0
     except ValueError:
       if IsDeviceAttached(self._device):
         raise errors.DeviceUnresponsiveError('Device may be offline.')
 
       return False
 
+  def TakeScreenshot(self, host_file):
+    """Saves a screenshot image to |host_file| on the host.
+
+    Args:
+      host_file: Absolute path to the image file to store on the host.
+    """
+    device_file = '%s/screenshot.png' % self.GetExternalStorage()
+    self.RunShellCommand('/system/bin/screencap -p %s' % device_file)
+    assert self._adb.Pull(device_file, host_file)
+    assert os.path.exists(host_file)
+
 
 class NewLineNormalizer(object):
   """A file-like object to normalize EOLs to '\n'.
 
   Pexpect runs adb within a pseudo-tty device (see
   http://www.noah.org/wiki/pexpect), so any '\n' printed by adb is written
   as '\r\n' to the logfile. Since adb already uses '\r\n' to terminate
   lines, the log ends up having '\r\r\n' at the end of each line. This
   filter replaces the above with a single '\n' in the data stream.
   """
   def __init__(self, output):
     self._output = output
 
   def write(self, data):
     data = data.replace('\r\r\n', '\n')
     self._output.write(data)
 
   def flush(self):
     self._output.flush()