Mojo C++ bindings: add a presubmit check to disallow adding new mojom targets with use_new_wrapper_…

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 2fad49d17a0218adb806f415e9ff3f74b1f63e42..2eb9eec6c84423886bab29117a84fba51e9ffd48 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -1498,6 +1498,32 @@ def _CheckIpcOwners(input_api, output_api):
   return results
 
 
+def _CheckMojoUsesNewWrapperTypes(input_api, output_api):
+  """Checks to make sure that all newly added mojom targets map array/map/string
+     to STL (for chromium) or WTF (for blink) types.
+     TODO(yzshen): remove this check once crbug.com/624136 is completed.
+  """
+  files = []
+  pattern = input_api.re.compile(r'use_new_wrapper_types.*false',
+                                 input_api.re.MULTILINE)
+
+  for f in input_api.AffectedFiles():
+    if not f.LocalPath().endswith(('.gyp', '.gypi', 'gn', 'gni')):
+      continue
+
+    for _, line in f.ChangedContents():
+      if pattern.search(line):
+        files.append(f)
+        break
+
+  if len(files):
+    return [output_api.PresubmitError(
+        'Do not introduce new mojom targets with use_new_wrapper_types set to '
+        'false. The mode is deprecated and will be removed soon.',
+        files)]
+  return []
+
+
 def _CheckAndroidToastUsage(input_api, output_api):
   """Checks that code uses org.chromium.ui.widget.Toast instead of
      android.widget.Toast (Chromium Toast doesn't force hardware
@@ -1962,6 +1988,7 @@ def _CommonChecks(input_api, output_api):
   results.extend(_CheckPydepsNeedsUpdating(input_api, output_api))
   results.extend(_CheckJavaStyle(input_api, output_api))
   results.extend(_CheckIpcOwners(input_api, output_api))
+  results.extend(_CheckMojoUsesNewWrapperTypes(input_api, output_api))
 
   if any('PRESUBMIT.py' == f.LocalPath() for f in input_api.AffectedFiles()):
     results.extend(input_api.canned_checks.RunUnitTestsInDirectory(