Add a presubmit check so that no new unit tests in content/ are added to the unit_tests target

chrome/PRESUBMIT.py

Index: chrome/PRESUBMIT.py
diff --git a/chrome/PRESUBMIT.py b/chrome/PRESUBMIT.py
index 087232f5923298f59755e94fd9abba7f0275a1f3..8bf83c5b73e0f1155dcf9f249eef52d5878b3f74 100644
--- a/chrome/PRESUBMIT.py
+++ b/chrome/PRESUBMIT.py
@@ -2,7 +2,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Makes sure that the chrome/ code is cpplint clean."""
+"""Presubmit script for changes affecting chrome/
+
+See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
+for more details about the presubmit API built into gcl.
+"""
+
+import re
 
 INCLUDE_CPP_FILES_ONLY = (
   r'.*\.cc$', r'.*\.h$'
@@ -40,11 +46,46 @@ EXCLUDE = (
   r'gcapi\.cc$',
 )
 
-def CheckChangeOnUpload(input_api, output_api):
-  results = []
+def _CheckChangeLintsClean(input_api, output_api):
+  """Makes sure that the chrome/ code is cpplint clean."""
   black_list = input_api.DEFAULT_BLACK_LIST + EXCLUDE
   sources = lambda x: input_api.FilterSourceFile(
     x, white_list=INCLUDE_CPP_FILES_ONLY, black_list=black_list)
-  results.extend(input_api.canned_checks.CheckChangeLintsClean(
-      input_api, output_api, sources))
+  return input_api.canned_checks.CheckChangeLintsClean(
+      input_api, output_api, sources)
+
+def _CheckNoContentUnitTestsInChrome(input_api, output_api):
+  """Makes sure that no unit tests from content/ are included in unit_tests."""
+  problems = []
+  for f in input_api.AffectedFiles():
+    if not f.LocalPath().endswith('chrome_tests.gypi'):
+      continue
+
+    for line_num, line in f.ChangedContents():
+      m = re.search(r"'(.*\/content\/.*unittest.*)'", line)
+      if m:
+        problems.append(m.group(1))
+
+  if not problems:
+    return []
+  return [output_api.PresubmitPromptWarning(
+      'Unit tests located in content/ should be added to the ' +
+      'content_tests.gypi:content_unittests target.',
+      items=problems)]
+
+def _CommonChecks(input_api, output_api):
+  """Checks common to both upload and commit."""
+  results = []
+  results.extend(_CheckNoContentUnitTestsInChrome(input_api, output_api))
+  return results
+
+def CheckChangeOnUpload(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
+  results.extend(_CheckChangeLintsClean(input_api, output_api))
+  return results
+
+def CheckChangeOnCommit(input_api, output_api):
+  results = []
+  results.extend(_CommonChecks(input_api, output_api))
   return results