[Android] Extract device blacklisting into its own module.

build/android/pylib/device/device_blacklist.py

Index: build/android/pylib/device/device_blacklist.py
diff --git a/build/android/pylib/device/device_blacklist.py b/build/android/pylib/device/device_blacklist.py
new file mode 100644
index 0000000000000000000000000000000000000000..996af8d23a7065c04809097206ff335d236cb5a4
--- /dev/null
+++ b/build/android/pylib/device/device_blacklist.py
@@ -0,0 +1,45 @@
+import json

[bulach, 2014/03/21 14:38:55]

nit: copyright notice

+import os
+
+from pylib import constants
+_BLACKLIST_JSON = os.path.join(
+    constants.DIR_SOURCE_ROOT,
+    os.environ.get('CHROMIUM_OUT_DIR', 'out'),
+    'bad_devices.json')
+

[bulach, 2014/03/21 14:38:55]

nit: need two \n between top-levels

+def ReadBlacklist():
+  """Reads the blacklist from the _BLACKLIST_JSON file.
+
+  Returns:
+    A list containing bad devices.
+  """
+  blacklist = []

[bulach, 2014/03/21 14:38:55]

nit: how about:

if not os.path.exists(_BLACKLIST_JSON):
  return []

with open(_BLACKLIST_JSON, 'r') as f:
  return json.load(f)

+  if os.path.exists(_BLACKLIST_JSON):
+    with open(_BLACKLIST_JSON, 'r') as f:
+      blacklist = json.load(f)
+  return blacklist
+

[bulach, 2014/03/21 14:38:55]

nit: another \n here, 30 and 41

+def WriteBlacklist(blacklist):
+  """Writes the provided blacklist to the _BLACKLIST_JSON file.
+
+  Args:
+    blacklist: list of bad devices to write to the _BLACKLIST_JSON file.
+  """
+  with open(_BLACKLIST_JSON, 'w') as f:
+    json.dump(list(set(blacklist)), f)
+
+def ExtendBlacklist(devices):
+  """Adds devices to _BLACKLIST_JSON file.
+
+  Args:
+    devices: list of bad devices to be added to the _BLACKLIST_JSON file.
+  """
+  blacklist = ReadBlacklist()
+  blacklist.extend(devices)
+  WriteBlacklist(blacklist)
+
+def ResetBlacklist():
+  """Erases the _BLACKLIST_JSON file if it exists."""
+  if os.path.exists(_BLACKLIST_JSON):
+    os.remove(_BLACKLIST_JSON)
+