PPAPI: Make API changes w/o IDL changes Warnings if generators have changed

ppapi/PRESUBMIT.py

Index: ppapi/PRESUBMIT.py
diff --git a/ppapi/PRESUBMIT.py b/ppapi/PRESUBMIT.py
index 0ae9b0e37e4e628af1beac742adf198ecda41a94..7d6a400bd4d50b638b19cc7a469ed9a8d1106160 100644
--- a/ppapi/PRESUBMIT.py
+++ b/ppapi/PRESUBMIT.py
@@ -159,6 +159,7 @@ def CheckChange(input_api, output_api):
   files = input_api.LocalPaths()
   h_files = []
   idl_files = []
+  generators_changed = False
 
   # Find all relevant .h and .idl files.
   for filename in files:
@@ -166,8 +167,10 @@ def CheckChange(input_api, output_api):
     name_parts = name.split(os.sep)
     if name_parts[0:2] == ['ppapi', 'c'] and ext == '.h':
       h_files.append('/'.join(name_parts[2:]))
-    if name_parts[0:2] == ['ppapi', 'api'] and ext == '.idl':
+    elif name_parts[0:2] == ['ppapi', 'api'] and ext == '.idl':
       idl_files.append('/'.join(name_parts[2:]))
+    elif name_parts[0:2] == ['ppapi', 'generators']:
+      generators_changed = True
 
   # Generate a list of all appropriate *.h and *.idl changes in this CL.
   both = h_files + idl_files
@@ -247,10 +250,20 @@ def CheckChange(input_api, output_api):
             long_text='\n'.join(missing_dev)))
 
   if missing_stable:
-    results.append(
-        output_api.PresubmitError(
-            'Missing PPAPI IDL for stable interface:',
-            long_text='\n'.join(missing_stable)))
+    # It might be okay that the header changed without a corresponding IDL
+    # change. E.g., comment indenting may have been changed. Treat this as a
+    # warning.
+    if generators_changed:
+      results.append(
+          output_api.PresubmitPromptWarning(
+              'Missing PPAPI IDL for stable interface (due to change in ' +
+              'generators?):',
+              long_text='\n'.join(missing_stable)))
+    else:
+      results.append(
+          output_api.PresubmitError(
+              'Missing PPAPI IDL for stable interface:',
+              long_text='\n'.join(missing_stable)))
 
   # Verify all *.h files match *.idl definitions, use:
   #   --test to prevent output to disk