[Extensions] More bindings improvements

extensions/renderer/resources/binding.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var Event = require('event_bindings').Event;
 var forEach = require('utils').forEach;
+// Note: Beware sneaky getters/setters when using GetAvailbility(). Use safe/raw
+// variables as arguments.
 var GetAvailability = requireNative('v8_context').GetAvailability;
 var exceptionHandler = require('uncaught_exception_handler');
 var lastError = require('lastError');
 var logActivity = requireNative('activityLogger');
 var logging = requireNative('logging');
 var process = requireNative('process');
 var schemaRegistry = requireNative('schema_registry');
 var schemaUtils = require('schemaUtils');
 var utils = require('utils');
 var sendRequestHandler = require('sendRequest');
@@ skipping 225 matching lines @@
 
   // Generates the bindings from the schema for |this.apiName_| and integrates
   // any custom bindings that might be present.
   generate: function() {
     // NB: It's important to load the schema during generation rather than
     // setting it beforehand so that we're more confident the schema we're
     // loading is real, and not one that was injected by a page intercepting
     // Binding.generate.
     // Additionally, since the schema is an object returned from a native
     // handler, its properties don't have the custom getters/setters that a page
-    // may have put on Object.prototype.
+    // may have put on Object.prototype, and the object is frozen by v8.
     var schema = schemaRegistry.GetSchema(this.apiName_);
 
     function shouldCheckUnprivileged() {
       var shouldCheck = 'unprivileged' in schema;
       if (shouldCheck)
         return shouldCheck;
 
       $Array.forEach(['functions', 'events'], function(type) {
         if ($Object.hasOwnProperty(schema, type)) {
           $Array.forEach(schema[type], function(node) {
@@ skipping 109 matching lines @@
                           ' already defined in ' + schema.namespace);
         }
 
         if (!isSchemaNodeSupported(functionDef, platform, manifestVersion)) {
           this.apiFunctions_.registerUnavailable(functionDef.name);
           return;
         }
 
         var apiFunction = {};
         apiFunction.definition = functionDef;
-        apiFunction.name = schema.namespace + '.' + functionDef.name;
+        var apiFunctionName = schema.namespace + '.' + functionDef.name;
+        apiFunction.name = apiFunctionName;
 
-        if (!GetAvailability(apiFunction.name).is_available ||
+        if (!GetAvailability(apiFunctionName).is_available ||
             (checkUnprivileged && !isSchemaAccessAllowed(functionDef))) {
           this.apiFunctions_.registerUnavailable(functionDef.name);
           return;
         }
 
         // TODO(aa): It would be best to run this in a unit test, but in order
         // to do that we would need to better factor this code so that it
         // doesn't depend on so much v8::Extension machinery.
         if (logging.DCHECK_IS_ON() &&
             schemaUtils.isFunctionSignatureAmbiguous(apiFunction.definition)) {
@@ skipping 157 matching lines @@
                     availability.message);
       return;
     }
 
     this.runHooks_(mod, schema);
     return mod;
   }
 };
 
 exports.$set('Binding', Binding);