PRESUBMIT: reject changes that add wstrings

We are trying to get rid of wstrings, but new code keeps getting
checked in that adds more.  This will help prevent future mistakes.

Review URL: http://codereview.chromium.org/7886019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@100974 0039d316-1c4b-4281-b951-d872f2087c98

PRESUBMIT.py

@@ -111,6 +111,23 @@ def _CheckNoIOStreamInHeaders(input_api, output_api):
   return []
 
 
+def _CheckNoNewWStrings(input_api, output_api):
+  """Checks to make sure we don't introduce use of wstrings."""
+  errors = []
+  for f in input_api.AffectedFiles():
+    for line_num, line in f.ChangedContents():
+      if not f.LocalPath().endswith(('.cc', '.h')):
+        continue
+
+      if 'wstring' in line:
+        errors.append(output_api.PresubmitError(
+            '%s, line %d: new code should not use wstrings.  If you are '
+            'calling an API that accepts a wstring, fix the API.'
+            % (f.LocalPath(), line_num)))
+
+  return errors
+
+
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
@@ -121,6 +138,7 @@ def _CommonChecks(input_api, output_api):
   results.extend(
     _CheckNoProductionCodeUsingTestOnlyFunctions(input_api, output_api))
   results.extend(_CheckNoIOStreamInHeaders(input_api, output_api))
+  results.extend(_CheckNoNewWStrings(input_api, output_api))
   return results