Improve handling of ArrayBuffers in composite objects.

tools/json_schema_compiler/idl_schema.py

Index: tools/json_schema_compiler/idl_schema.py
diff --git a/tools/json_schema_compiler/idl_schema.py b/tools/json_schema_compiler/idl_schema.py
index d65746a210af0d24649677719f8291107a474fa6..28f2a3b61449776d270ec161a0b91e2995c042fa 100644
--- a/tools/json_schema_compiler/idl_schema.py
+++ b/tools/json_schema_compiler/idl_schema.py
@@ -190,16 +190,17 @@ class Typeref(object):
       properties['type'] = 'integer'
     elif self.typeref == 'any':
       properties['type'] = 'any'
-    elif self.typeref == 'ArrayBuffer' or self.typeref == 'object':
+    elif self.typeref == 'object':
       properties['type'] = 'object'
       if 'additionalProperties' not in properties:
         properties['additionalProperties'] = {}
       properties['additionalProperties']['type'] = 'any'
       instance_of = self.parent.GetProperty('instanceOf')
-      if self.typeref == 'ArrayBuffer':
-        properties['isInstanceOf'] = 'ArrayBuffer'
-      elif instance_of:
+      if instance_of:
         properties['isInstanceOf'] = instance_of
+    elif self.typeref == 'ArrayBuffer':
+      properties['type'] = 'binary'
+      properties['isInstanceOf'] = 'ArrayBuffer'
     elif self.typeref is None:
       properties['type'] = 'function'
     else: