Update from https://crrev.com/328418

build/android/pylib/device/adb_wrapper.py

 # Copyright 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.
 
 """This module wraps Android's adb tool.
 
 This is a thin wrapper around the adb interface. Any additional complexity
 should be delegated to a higher level (ex. DeviceUtils).
 """
 
@@ skipping 432 matching lines @@
       path: Local path to store the backup file.
       packages: List of to packages to be backed up.
       apk: (optional) If set include the .apk files in the archive.
       shared: (optional) If set buckup the device's SD card.
       nosystem: (optional) If set exclude system applications.
       include_all: (optional) If set back up all installed applications and
         |packages| is optional.
       timeout: (optional) Timeout per try in seconds.
       retries: (optional) Number of retries to attempt.
     """
-    cmd = ['backup', path]
+    cmd = ['backup', '-f', path]
     if apk:
       cmd.append('-apk')
     if shared:
       cmd.append('-shared')
     if nosystem:
       cmd.append('-nosystem')
     if include_all:
       cmd.append('-all')
     if packages:
       cmd.extend(packages)
@@ skipping 71 matching lines @@
 
     Args:
       timeout: (optional) Timeout per try in seconds.
       retries: (optional) Number of retries to attempt.
     """
     output = self._RunDeviceAdbCmd(['root'], timeout, retries)
     if 'cannot' in output:
       raise device_errors.AdbCommandFailedError(
           ['root'], output, device_serial=self._device_serial)
 
+  def Emu(self, cmd, timeout=_DEFAULT_TIMEOUT,
+               retries=_DEFAULT_RETRIES):
+    """Runs an emulator console command.
+
+    See http://developer.android.com/tools/devices/emulator.html#console
+
+    Args:
+      cmd: The command to run on the emulator console.
+      timeout: (optional) Timeout per try in seconds.
+      retries: (optional) Number of retries to attempt.
+
+    Returns:
+      The output of the emulator console command.
+    """
+    if isinstance(cmd, basestring):
+      cmd = [cmd]
+    return self._RunDeviceAdbCmd(['emu'] + cmd, timeout, retries)
+
   @property
   def is_emulator(self):
     return _EMULATOR_RE.match(self._device_serial)
 
   @property
   def is_ready(self):
     try:
       return self.GetState() == _READY_STATE
     except device_errors.CommandFailedError:
       return False