Add Pylint for docs server.

chrome/common/extensions/docs/server2/PRESUBMIT.py

Index: chrome/common/extensions/docs/server2/PRESUBMIT.py
diff --git a/chrome/common/extensions/docs/server2/PRESUBMIT.py b/chrome/common/extensions/docs/server2/PRESUBMIT.py
index b4332e203e920414cb1a2a9094e607486c3ae8eb..047dee36296172b80d07e4d58cad84bd920c7f74 100644
--- a/chrome/common/extensions/docs/server2/PRESUBMIT.py
+++ b/chrome/common/extensions/docs/server2/PRESUBMIT.py
@@ -85,6 +85,13 @@ def _CheckYamlConsistency(input_api, output_api):
 
 def _RunPresubmit(input_api, output_api):
   _BuildServer(input_api)
+  # For now, print any lint errors. When these have been eliminated,
+  # move these into the warning list below.
+  # See crbug.com/434363 and crbug.com/461130.
+  lint_errors = input_api.canned_checks.RunPylint(input_api, output_api)
+  if lint_errors:
+    print(lint_errors)

[not at google - send to devlin, 2015/02/24 01:01:25]

if you don't do the ''.join thing then it'll format it as a list rather than on
every line, which will look silly.

[tfarina, 2015/02/24 01:05:35]

it was not possible to do a join in the list:
AttributeError: 'list' object has no attribute 'join'

The current output is: http://pastebin.com/Cz9xeidV

[not at google - send to devlin, 2015/02/24 01:07:30]

If I said lint_errors.join('') before, I meant ''.join(lint_errors).

+
   return (
       _WarnIfAppYamlHasntChanged(input_api, output_api) +
       _CheckYamlConsistency(input_api, output_api) +