JSON Schema Compiler supports functions as PropertyTypes.

tools/json_schema_compiler/model.py

Index: tools/json_schema_compiler/model.py
diff --git a/tools/json_schema_compiler/model.py b/tools/json_schema_compiler/model.py
index 5453e11c40a11a6abe9425d5df2a8e997ab726b5..9bdf4048b61f5ee954e380d969ade952accf622f 100644
--- a/tools/json_schema_compiler/model.py
+++ b/tools/json_schema_compiler/model.py
@@ -212,6 +212,8 @@ class Property(object):
         # self.properties will already have some value from |_AddProperties|.
         self.properties.update(type_.properties)
         self.functions = type_.functions
+      elif json_type == 'function':
+        self.type_ = PropertyType.FUNCTION
       elif json_type == 'binary':
         self.type_ = PropertyType.BINARY
       else:
@@ -293,6 +295,7 @@ class PropertyType(object):
   REF = _Info(False, "REF")
   CHOICES = _Info(False, "CHOICES")
   OBJECT = _Info(False, "OBJECT")
+  FUNCTION = _Info(False, "FUNCTION")
   BINARY = _Info(False, "BINARY")
   ANY = _Info(False, "ANY")
   ADDITIONAL_PROPERTIES = _Info(False, "ADDITIONAL_PROPERTIES")
@@ -358,8 +361,8 @@ def _AddProperties(model, json, from_json=False, from_client=False):
     # the instances of functions-on-properties in the extension APIs are all
     # handled in pure Javascript on the render process (and .: never reach
     # C++ let alone the browser).
-    if property_json.get('type') == 'function':
-      continue
+    #if property_json.get('type') == 'function':
+      #continue

[not at google - send to devlin, 2012/07/25 01:32:33]

delete this and the whole comment above, it's no longer relevant.

[chebert, 2012/07/25 18:38:30]

Done.

     model.properties[name] = Property(
         model,
         name,