Update from https://crrev.com/316786

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 235 matching lines @@
       except ValueError:
         logging.warning('exit status of shell command %r missing.', command)
         raise device_errors.AdbShellCommandFailedError(
             command, output, status=None, device_serial=self._device_serial)
       output = output[:output_end]
       if status != expect_status:
         raise device_errors.AdbShellCommandFailedError(
             command, output, status=status, device_serial=self._device_serial)
     return output
 
+  def IterShell(self, command, timeout):
+    """Runs a shell command and returns an iterator over its output lines.
+
+    Args:
+      command: A string with the shell command to run.
+      timeout: Timeout in seconds.
+
+    Yields:
+      The output of the command line by line.
+    """
+    args = ['shell', command]
+    return cmd_helper.IterCmdOutputLines(
+      self._BuildAdbCmd(args, self._device_serial), timeout=timeout)
+
   def Ls(self, path, timeout=_DEFAULT_TIMEOUT, retries=_DEFAULT_RETRIES):
     """List the contents of a directory on the device.
 
     Args:
       path: Path on the device filesystem.
       timeout: (optional) Timeout per try in seconds.
       retries: (optional) Number of retries to attempt.
 
     Returns:
       A list of pairs (filename, stat) for each file found in the directory,
@@ skipping 13 matching lines @@
     lines = self._RunDeviceAdbCmd(
         cmd, timeout=timeout, retries=retries).splitlines()
     if lines:
       return [ParseLine(line) for line in lines]
     else:
       raise device_errors.AdbCommandFailedError(
           cmd, 'path does not specify an accessible directory in the device',
           device_serial=self._device_serial)
 
   def Logcat(self, clear=False, dump=False, filter_spec=None,
-             logcat_format=None, timeout=None):
-    """Get an iterator over the logcat output.
+             logcat_format=None, timeout=None, retries=_DEFAULT_RETRIES):
+    """Get an iterable over the logcat output.
 
     Args:
-      filter_spec: (optional) Spec to filter the logcat.
-      timeout: (optional) Timeout per try in seconds.
+      clear: If true, clear the logcat.
+      dump: If true, dump the current logcat contents.
+      filter_spec: If set, spec to filter the logcat.
+      logcat_format: If set, the format in which the logcat should be output.
+        Options include "brief", "process", "tag", "thread", "raw", "time",
+        "threadtime", and "long"
+      timeout: (optional) If set, timeout per try in seconds. If clear or dump
+        is set, defaults to _DEFAULT_TIMEOUT.
+      retries: (optional) If clear or dump is set, the number of retries to
+        attempt. Otherwise, does nothing.
 
     Yields:
       logcat output line by line.
     """
     cmd = ['logcat']
+    use_iter = True
     if clear:
       cmd.append('-c')
+      use_iter = False
     if dump:
       cmd.append('-d')
+      use_iter = False
     if logcat_format:
       cmd.extend(['-v', logcat_format])
     if filter_spec is not None:
       cmd.append(filter_spec)
-    return self._IterRunDeviceAdbCmd(cmd, timeout)
+
+    if use_iter:
+      return self._IterRunDeviceAdbCmd(cmd, timeout)
+    else:
+      timeout = timeout if timeout is not None else _DEFAULT_TIMEOUT
+      return self._RunDeviceAdbCmd(cmd, timeout, retries)
 
   def Forward(self, local, remote, timeout=_DEFAULT_TIMEOUT,
               retries=_DEFAULT_RETRIES):
     """Forward socket connections from the local socket to the remote socket.
 
     Sockets are specified by one of:
       tcp:<port>
       localabstract:<unix domain socket name>
       localreserved:<unix domain socket name>
       localfilesystem:<unix domain socket name>
@@ skipping 167 matching lines @@
     """Restarts the adbd daemon with root permissions, if possible.
 
     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)