Validation of extension api callback and event parameters in DEBUG

chrome/renderer/resources/event_bindings.js

Index: chrome/renderer/resources/event_bindings.js
diff --git a/chrome/renderer/resources/event_bindings.js b/chrome/renderer/resources/event_bindings.js
index 5fb16f9584f7003c3363d366ce37ff7c7a6c1d20..3def161f7d300c292ca337e6668f69e76a838ff2 100644
--- a/chrome/renderer/resources/event_bindings.js
+++ b/chrome/renderer/resources/event_bindings.js
@@ -24,9 +24,24 @@ var chrome = chrome || {};
   //   chrome.tabs.onChanged.addListener(function(data) { alert(data); });
   //   chromeHidden.Event.dispatch("tab-changed", "hi");
   // will result in an alert dialog that says 'hi'.
-  chrome.Event = function(opt_eventName) {
+  chrome.Event = function(opt_eventName, opt_argSchemas) {
     this.eventName_ = opt_eventName;
     this.listeners_ = [];
+
+    // Validate event parameters if we are in debug.     
+    if (opt_argSchemas &&
+        chromeHidden.validateCallbacks &&
+        chromeHidden.validate) {
+
+      this.validate_ = function(args) {
+        try {
+          chromeHidden.validate(args, opt_argSchemas);
+        } catch (exception) {
+          return "Event validation error during " + opt_eventName + " -- " +
+                 exception;
+        }
+      }
+    }
   };
 
   // A map of event names to the event object that is registered to that name.
@@ -45,7 +60,7 @@ var chrome = chrome || {};
       if (args) {
         args = JSON.parse(args);
       }
-      attachedNamedEvents[name].dispatch.apply(
+      return attachedNamedEvents[name].dispatch.apply(
           attachedNamedEvents[name], args);
     }
   };
@@ -106,6 +121,12 @@ var chrome = chrome || {};
   // arguments to this function each listener.
   chrome.Event.prototype.dispatch = function(varargs) {
     var args = Array.prototype.slice.call(arguments);
+    if (this.validate_) {
+      var validationErrors = this.validate_(args);
+      if (validationErrors) {
+        return validationErrors;
+      }
+    }
     for (var i = 0; i < this.listeners_.length; i++) {
       try {
         this.listeners_[i].apply(null, args);