Add a few extra error messages to help catch typos in schemas.

chrome/renderer/resources/json_schema.js

Index: chrome/renderer/resources/json_schema.js
===================================================================
--- chrome/renderer/resources/json_schema.js	(revision 14729)
+++ chrome/renderer/resources/json_schema.js	(working copy)
@@ -71,7 +71,9 @@
   numberMaxValue: "Value must not be greater than *.",
   numberMaxDecimal: "Value must not have more than * decimal places.",
   invalidType: "Expected '*' but got '*'.",
-  invalidChoice: "Value does not match any valid type choices."
+  invalidChoice: "Value does not match any valid type choices.",
+  invalidPropertyType: "Missing property type.",
+  schemaRequired: "Schema value required.",
 };
 
 /**
@@ -121,6 +123,11 @@
                                                            opt_path) {
   var path = opt_path || "";
 
+  if (!schema) {
+    this.addError(path, "schemaRequired");
+    return;
+  }
+
   // If the schema has an extends property, the instance must validate against
   // that schema too.
   if (schema.extends)
@@ -209,7 +216,9 @@
                                                                  schema, path) {
   for (var prop in schema.properties) {
     var propPath = path ? path + "." + prop : prop;
-    if (prop in instance && instance[prop] !== null &&
+    if (!schema.properties[prop]) {
+      this.addError(propPath, "invalidPropertyType");

[Aaron Boodman, 2009/04/28 20:21:31]

This branch will get entered when schema.properties[prop] is defined, but
contains any falsy value like: false, 0, undefined, or null. Is that what you
intended? I guess I'm not sure what this is trying to test.

[Erik does not do reviews, 2009/04/28 20:29:34]

No.  I'm looking for undefined.  The problem I'm testing for is when in the
schema you have something like this:
properties: {
  title: chromium.types.string
}

instead of

properties: {
  title: chromium.types.str
}

So I'll change to test specifically against undefined.

+    } else if (prop in instance && instance[prop] !== null &&
         instance[prop] !== undefined) {
       this.validate(instance[prop], schema.properties[prop], propPath);
     } else if (!schema.properties[prop].optional) {