Sanitize inheritance in callers of utils.expose

extensions/renderer/resources/event.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.
 
+// TODO(robwu): Fix indentation.
+
   var exceptionHandler = require('uncaught_exception_handler');
   var eventNatives = requireNative('event_natives');
   var logging = requireNative('logging');
   var schemaRegistry = requireNative('schema_registry');
   var sendRequest = require('sendRequest').sendRequest;
   var utils = require('utils');
   var validate = require('schemaUtils').validate;
 
   // Schemas for the rule-style functions on the events API that
   // only need to be generated occasionally, so populate them lazily.
   var ruleFunctionSchemas = {
+    __proto__: null,
     // These values are set lazily:
     // addRules: {},
     // getRules: {},
     // removeRules: {}
   };
 
   // This function ensures that |ruleFunctionSchemas| is populated.
   function ensureRuleSchemasLoaded() {
     if (ruleFunctionSchemas.addRules)
       return;
     var eventsSchema = schemaRegistry.GetSchema("events");
     var eventType = utils.lookup(eventsSchema.types, 'id', 'events.Event');
 
     ruleFunctionSchemas.addRules =
         utils.lookup(eventType.functions, 'name', 'addRules');
     ruleFunctionSchemas.getRules =
         utils.lookup(eventType.functions, 'name', 'getRules');
     ruleFunctionSchemas.removeRules =
         utils.lookup(eventType.functions, 'name', 'removeRules');
   }
 
   // A map of event names to the event object that is registered to that name.
-  var attachedNamedEvents = {};
+  var attachedNamedEvents = {__proto__: null};
 
   // A map of functions that massage event arguments before they are dispatched.
   // Key is event name, value is function.
-  var eventArgumentMassagers = {};
+  var eventArgumentMassagers = {__proto__: null};
 
   // An attachment strategy for events that aren't attached to the browser.
   // This applies to events with the "unmanaged" option and events without
   // names.
-  var NullAttachmentStrategy = function(event) {
+  function NullAttachmentStrategy(event) {
     this.event_ = event;
-  };
+  }
+  $Object.setPrototypeOf(NullAttachmentStrategy.prototype, null);
+
   NullAttachmentStrategy.prototype.onAddedListener =
       function(listener) {
   };
   NullAttachmentStrategy.prototype.onRemovedListener =
       function(listener) {
   };
   NullAttachmentStrategy.prototype.detach = function(manual) {
   };
   NullAttachmentStrategy.prototype.getListenersByIDs = function(ids) {
     // |ids| is for filtered events only.
     return this.event_.listeners;
   };
 
   // Handles adding/removing/dispatching listeners for unfiltered events.
-  var UnfilteredAttachmentStrategy = function(event) {
+  function UnfilteredAttachmentStrategy(event) {
     this.event_ = event;
-  };
+  }
+  $Object.setPrototypeOf(UnfilteredAttachmentStrategy.prototype, null);
 
   UnfilteredAttachmentStrategy.prototype.onAddedListener =
       function(listener) {
     // Only attach / detach on the first / last listener removed.
     if (this.event_.listeners.length == 0)
       eventNatives.AttachEvent(this.event_.eventName);
   };
 
   UnfilteredAttachmentStrategy.prototype.onRemovedListener =
       function(listener) {
     if (this.event_.listeners.length == 0)
       this.detach(true);
   };
 
   UnfilteredAttachmentStrategy.prototype.detach = function(manual) {
     eventNatives.DetachEvent(this.event_.eventName, manual);
   };
 
   UnfilteredAttachmentStrategy.prototype.getListenersByIDs = function(ids) {
     // |ids| is for filtered events only.
     return this.event_.listeners;
   };
 
-  var FilteredAttachmentStrategy = function(event) {
+  function FilteredAttachmentStrategy(event) {
     this.event_ = event;
-    this.listenerMap_ = {};
-  };
+    this.listenerMap_ = {__proto__: null};
+  }
+  $Object.setPrototypeOf(FilteredAttachmentStrategy.prototype, null);
 
-  FilteredAttachmentStrategy.idToEventMap = {};
+  utils.defineProperty(FilteredAttachmentStrategy, 'idToEventMap',
+      {__proto__: null});
 
   FilteredAttachmentStrategy.prototype.onAddedListener = function(listener) {
     var id = eventNatives.AttachFilteredEvent(this.event_.eventName,
                                               listener.filters || {});
     if (id == -1)
       throw new Error("Can't add listener");
     listener.id = id;
     this.listenerMap_[id] = listener;
     FilteredAttachmentStrategy.idToEventMap[id] = this.event_;
   };
@@ skipping 18 matching lines @@
   };
 
   FilteredAttachmentStrategy.prototype.getListenersByIDs = function(ids) {
     var result = [];
     for (var i = 0; i < ids.length; i++)
       $Array.push(result, this.listenerMap_[ids[i]]);
     return result;
   };
 
   function parseEventOptions(opt_eventOptions) {
-    function merge(dest, src) {
-      for (var k in src) {
-        if (!$Object.hasOwnProperty(dest, k)) {
-          dest[k] = src[k];
-        }
-      }
-    }
-
-    var options = $Object.assign({}, opt_eventOptions || {});
-    merge(options, {
+    return $Object.assign({
+      __proto__: null,
+    }, {
       // Event supports adding listeners with filters ("filtered events"), for
       // example as used in the webNavigation API.
       //
       // event.addListener(listener, [filter1, filter2]);
       supportsFilters: false,
 
       // Events supports vanilla events. Most APIs use these.
       //
       // event.addListener(listener);
       supportsListeners: true,
 
       // Event supports adding rules ("declarative events") rather than
       // listeners, for example as used in the declarativeWebRequest API.
       //
       // event.addRules([rule1, rule2]);
       supportsRules: false,
 
       // Event is unmanaged in that the browser has no knowledge of its
       // existence; it's never invoked, doesn't keep the renderer alive, and
       // the bindings system has no knowledge of it.
       //
       // Both events created by user code (new chrome.Event()) and messaging
       // events are unmanaged, though in the latter case the browser *does*
       // interact indirectly with them via IPCs written by hand.
       unmanaged: false,
-    });
-    return options;
-  };
+    }, opt_eventOptions);
+  }
 
   // Event object.  If opt_eventName is provided, this object represents
   // the unique instance of that named event, and dispatching an event
   // with that name will route through this object's listeners. Note that
   // opt_eventName is required for events that support rules.
   //
   // Example:
   //   var Event = require('event_bindings').Event;
   //   chrome.tabs.onChanged = new Event("tab-changed");
   //   chrome.tabs.onChanged.addListener(function(data) { alert(data); });
   //   Event.dispatch("tab-changed", "hi");
   // will result in an alert dialog that says 'hi'.
   //
   // If opt_eventOptions exists, it is a dictionary that contains the boolean
   // entries "supportsListeners" and "supportsRules".
   // If opt_webViewInstanceId exists, it is an integer uniquely identifying a
   // <webview> tag within the embedder. If it does not exist, then this is an
   // extension event rather than a <webview> event.
-  var EventImpl = function(opt_eventName, opt_argSchemas, opt_eventOptions,
-                           opt_webViewInstanceId) {
+  function EventImpl(opt_eventName, opt_argSchemas, opt_eventOptions,
+                     opt_webViewInstanceId) {
     this.eventName = opt_eventName;
     this.argSchemas = opt_argSchemas;
     this.listeners = [];
     this.eventOptions = parseEventOptions(opt_eventOptions);
     this.webViewInstanceId = opt_webViewInstanceId || 0;
 
     if (!this.eventName) {
       if (this.eventOptions.supportsRules)
         throw new Error("Events that support rules require an event name.");
       // Events without names cannot be managed by the browser by definition
       // (the browser has no way of identifying them).
       this.eventOptions.unmanaged = true;
     }
 
     // Track whether the event has been destroyed to help track down the cause
     // of http://crbug.com/258526.
     // This variable will eventually hold the stack trace of the destroy call.
     // TODO(kalman): Delete this and replace with more sound logic that catches
     // when events are used without being *attached*.
     this.destroyed = null;
 
     if (this.eventOptions.unmanaged)
       this.attachmentStrategy = new NullAttachmentStrategy(this);
     else if (this.eventOptions.supportsFilters)
       this.attachmentStrategy = new FilteredAttachmentStrategy(this);
     else
       this.attachmentStrategy = new UnfilteredAttachmentStrategy(this);
-  };
+  }
+  $Object.setPrototypeOf(EventImpl.prototype, null);
 
   // callback is a function(args, dispatch). args are the args we receive from
   // dispatchEvent(), and dispatch is a function(args) that dispatches args to
   // its listeners.
   function registerArgumentMassager(name, callback) {
     if (eventArgumentMassagers[name])
       throw new Error("Massager already registered for event: " + name);
     eventArgumentMassagers[name] = callback;
   }
 
@@ skipping 176 matching lines @@
 
   EventImpl.prototype.addRules = function(rules, opt_cb) {
     if (!this.eventOptions.supportsRules)
       throw new Error("This event does not support rules.");
 
     // Takes a list of JSON datatype identifiers and returns a schema fragment
     // that verifies that a JSON object corresponds to an array of only these
     // data types.
     function buildArrayOfChoicesSchema(typesList) {
       return {
+        __proto__: null,
         'type': 'array',
         'items': {
-          'choices': $Array.map(typesList, function(el) {return {'$ref': el};})
+          __proto__: null,
+          'choices': $Array.map(typesList, function(el) {
+            return {
+              __proto__: null,
+              '$ref': el,
+            };
+          }),
         }
       };
-    };
+    }
 
     // Validate conditions and actions against specific schemas of this
     // event object type.
     // |rules| is an array of JSON objects that follow the Rule type of the
     // declarative extension APIs. |conditions| is an array of JSON type
     // identifiers that are allowed to occur in the conditions attribute of each
     // rule. Likewise, |actions| is an array of JSON type identifiers that are
     // allowed to occur in the actions attribute of each rule.
     function validateRules(rules, conditions, actions) {
       var conditionsSchema = buildArrayOfChoicesSchema(conditions);
@@ skipping 10 matching lines @@
     }
 
     validateRules(rules,
                   this.eventOptions.conditions,
                   this.eventOptions.actions);
 
     ensureRuleSchemasLoaded();
     // We remove the first parameter from the validation to give the user more
     // meaningful error messages.
     validate([this.webViewInstanceId, rules, opt_cb],
-             $Array.splice(
-                 $Array.slice(ruleFunctionSchemas.addRules.parameters), 1));
+        $Array.slice(ruleFunctionSchemas.addRules.parameters, 1));
     sendRequest(
       "events.addRules",
       [this.eventName, this.webViewInstanceId, rules,  opt_cb],
       ruleFunctionSchemas.addRules.parameters);
   }
 
   EventImpl.prototype.removeRules = function(ruleIdentifiers, opt_cb) {
     if (!this.eventOptions.supportsRules)
       throw new Error("This event does not support rules.");
     ensureRuleSchemasLoaded();
     // We remove the first parameter from the validation to give the user more
     // meaningful error messages.
     validate([this.webViewInstanceId, ruleIdentifiers, opt_cb],
-             $Array.splice(
-                 $Array.slice(ruleFunctionSchemas.removeRules.parameters), 1));
+        $Array.slice(ruleFunctionSchemas.removeRules.parameters, 1));
     sendRequest("events.removeRules",
                 [this.eventName,
                  this.webViewInstanceId,
                  ruleIdentifiers,
                  opt_cb],
                 ruleFunctionSchemas.removeRules.parameters);
   }
 
   EventImpl.prototype.getRules = function(ruleIdentifiers, cb) {
     if (!this.eventOptions.supportsRules)
       throw new Error("This event does not support rules.");
     ensureRuleSchemasLoaded();
     // We remove the first parameter from the validation to give the user more
     // meaningful error messages.
     validate([this.webViewInstanceId, ruleIdentifiers, cb],
-             $Array.splice(
-                 $Array.slice(ruleFunctionSchemas.getRules.parameters), 1));
+        $Array.slice(ruleFunctionSchemas.getRules.parameters, 1));
 
     sendRequest(
       "events.getRules",
       [this.eventName, this.webViewInstanceId, ruleIdentifiers, cb],
       ruleFunctionSchemas.getRules.parameters);
   }
 
   function Event() {
     privates(Event).constructPrivate(this, arguments);
   }
@@ skipping 10 matching lines @@
       'getRules',
     ],
   });
 
   // NOTE: Event is (lazily) exposed as chrome.Event from dispatcher.cc.
   exports.$set('Event', Event);
 
   exports.$set('dispatchEvent', dispatchEvent);
   exports.$set('parseEventOptions', parseEventOptions);
   exports.$set('registerArgumentMassager', registerArgumentMassager);