[presubmit] Add python formatting check

Add check_python parameter to CheckPatchFormatted to check that python
files are well formatted.

Change-Id: Ibd20d5ec9d1d5142a26f7f4cd5f05c51223da6ca
Reviewed-on: https://chromium-review.googlesource.com/1081342
Commit-Queue: Nodir Turakulov <nodir@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>

presubmit_canned_checks.py

@@ -1055,12 +1055,19 @@ def PanProjectChecks(input_api, output_api,
   return results
 
 
-def CheckPatchFormatted(input_api, output_api, check_js=False):
+def CheckPatchFormatted(
+    input_api, output_api, check_js=False, check_python=False):
   import git_cl
-  cmd = ['-C', input_api.change.RepositoryRoot(),
-         'cl', 'format', '--dry-run', '--presubmit']
+
+  display_args = []
   if check_js:
-    cmd.append('--js')
+    display_args.append('--js')
+  if check_python:
+    # --python requires --full
+    display_args.extend(['--python', '--full'])
+
+  cmd = ['-C', input_api.change.RepositoryRoot(),
+         'cl', 'format', '--dry-run', '--presubmit'] + display_args
   presubmit_subdir = input_api.os_path.relpath(
       input_api.PresubmitLocalPath(), input_api.change.RepositoryRoot())
   if presubmit_subdir.startswith('..') or presubmit_subdir == '.':
@@ -1076,10 +1083,11 @@ def CheckPatchFormatted(input_api, output_api, check_js=False):
       short_path = presubmit_subdir
     else:
       short_path = input_api.basename(input_api.change.RepositoryRoot())
+    display_args.append(presubmit_subdir)
     return [output_api.PresubmitPromptWarning(
       'The %s directory requires source formatting. '
-      'Please run: git cl format %s%s' %
-      (short_path, '--js ' if check_js else '', presubmit_subdir))]
+      'Please run: git cl format %s' %
+      (short_path, ' '.join(display_args)))]
   # As this is just a warning, ignore all other errors if the user
   # happens to have a broken clang-format, doesn't use git, etc etc.
   return []