[Android] Add functionality to flash devices.

build/android/devil/android/sdk/fastboot.py

Index: build/android/devil/android/sdk/fastboot.py
diff --git a/build/android/devil/android/sdk/fastboot.py b/build/android/devil/android/sdk/fastboot.py
new file mode 100644
index 0000000000000000000000000000000000000000..ab84d0a42fed16ce2c9763ca60efcdd7a1c8bc2d
--- /dev/null
+++ b/build/android/devil/android/sdk/fastboot.py
@@ -0,0 +1,85 @@
+# Copyright 2015 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 fastboot tool.
+
+This is a thin wrapper around the fastboot interface. Any additional complexity
+should be delegated to a higher level (ex. FastbootUtils).
+"""
+
+import os
+
+from devil.android import device_errors
+from devil.utils import cmd_helper
+from pylib import constants
+
+_FASTBOOT_CMD = os.path.join(
+    constants.ANDROID_SDK_ROOT, 'platform-tools', 'fastboot')
+
+
+class Fastboot(object):
+
+  def __init__(self, device_serial):
+    """Initializes the FastbootWrapper.
+
+    Args:
+      device_serial: The device serial number as a string.
+    """
+    if not device_serial:
+      raise ValueError('A device serial must be specified')
+    self._device_serial = str(device_serial)
+
+  def _RunFastbootCommand(self, cmd):

[jbudorick, 2015/10/29 13:29:22]

Should any of these functions be timeout/retry decorated? I imagine it might
make sense to at least have timeouts by default...

[rnephew (Reviews Here), 2015/10/29 16:37:35]

Since most of the commands are rebooting commands, if it times out mid reboot
the rest will fail since its no longer in fastboot mode; so I'm not sure that
retries make sense for all of them. I'm also going to enforce high minimum
timeouts for the reboots and flashes. I dont think its a good idea having them
interrupted. Its better to have it wait (random number) minutes than brick a
device.

+    """Run a command line command using the fastboot android tool.
+
+    Args:
+      cmd: Command to run. Must be list of args, the first one being the command
+
+    Returns:
+      output of command.
+
+    Raises:
+      TypeError: If cmd is not of type list.
+    """
+    if type(cmd) == list:
+      cmd = [_FASTBOOT_CMD, '-s', self._device_serial] + cmd
+    else:
+      raise TypeError(
+          'Command for _RunFastbootCommand must be a list.')
+    status, output = cmd_helper.GetCmdStatusAndOutput(cmd)
+    if int(status) != 0:
+      raise device_errors.FastbootCommandFailedError(
+          cmd, output, status, self._device_serial)
+    return output
+
+  def Flash(self, partition, image):
+    """Flash partition with img.
+
+    Args:
+      partition: Partition to be flashed.
+      image: location of image to flash with.
+    """
+    self._RunFastbootCommand(['flash', partition, image])
+
+  def Devices(self):
+    """Outputs list of devices in fastboot mode."""
+    output = self._RunFastbootCommand(['devices'])
+    return [line.split()[0] for line in output.splitlines()]
+
+  def RebootBootloader(self):
+    """Reboot from fastboot, into fastboot."""
+    self._RunFastbootCommand(['reboot-bootloader'])
+
+  def Reboot(self):
+    """Reboot from fastboot to normal usage"""
+    self._RunFastbootCommand(['reboot'])
+
+  def SetOemOffModeCharge(self, value):
+    """Sets off mode charging
+
+    Args:
+      value: boolean value to set off-mode-charging on or off.
+    """
+    self._RunFastbootCommand(
+        ['oem', 'off-mode-charge', str(int(value))])