Re-enable PRESUBMIT check for empty unique_ptr<> rvalue

ui/PRESUBMIT.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Presubmit script for ui.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
@@ skipping 15 matching lines @@
       # bar = std::unique_ptr<T>(foo);
       # But allow:
       # return std::unique_ptr<T[]>(foo);
       # bar = std::unique_ptr<T[]>(foo);
       if input_api.re.search(
               r'(=|\breturn)\s*std::unique_ptr<[^\[\]>]+>\([^)]+\)', line):
         errors.append(output_api.PresubmitError(
             ('%s:%d uses explicit std::unique_ptr constructor. ' +
              'Use base::MakeUnique<T>() or base::WrapUnique() instead.') %
             (f.LocalPath(), line_number)))
-      # TODO(sky): this incorrectly catches templates. Fix and reenable.
       # Disallow:
       # std::unique_ptr<T>()
-      # if input_api.re.search(r'\bstd::unique_ptr<.*?>\(\)', line):
-      #   errors.append(output_api.PresubmitError(
-      #       '%s:%d uses std::unique_ptr<T>(). Use nullptr instead.' %
-      #       (f.LocalPath(), line_number)))
+      if input_api.re.search(r'\bstd::unique_ptr<[^<>]+>\(\)', line):
+        errors.append(output_api.PresubmitError(
+            '%s:%d uses std::unique_ptr<T>(). Use nullptr instead.' %
+            (f.LocalPath(), line_number)))
   return errors
 
 
 def CheckChange(input_api, output_api):
   results = []
   results += CheckUniquePtr(input_api, output_api)
   return results
 
 
 def CheckChangeOnUpload(input_api, output_api):
   return CheckChange(input_api, output_api)
 
 
 def CheckChangeOnCommit(input_api, output_api):
   return CheckChange(input_api, output_api)