Add sample extension that allows setting plugin-specific content settings.

chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/event_target.js

Index: chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/event_target.js
diff --git a/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/event_target.js b/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/event_target.js
new file mode 100644
index 0000000000000000000000000000000000000000..5bcb41d61384a3d4421ac7c88edfaf2930584e45
--- /dev/null
+++ b/chrome/common/extensions/docs/examples/extensions/plugin_settings/domui/js/cr/event_target.js
@@ -0,0 +1,104 @@
+// Copyright (c) 2010 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.
+
+/**
+ * @fileoverview This contains an implementation of the EventTarget interface
+ * as defined by DOM Level 2 Events.
+ */
+
+cr.define('cr', function() {
+
+  /**
+   * Creates a new EventTarget. This class implements the DOM level 2
+   * EventTarget interface and can be used wherever those are used.
+   * @constructor
+   */
+  function EventTarget() {
+  }
+
+  EventTarget.prototype = {
+
+    /**
+     * Adds an event listener to the target.
+     * @param {string} type The name of the event.
+     * @param {!Function|{handleEvent:Function}} handler The handler for the
+     *     event. This is called when the event is dispatched.
+     */
+    addEventListener: function(type, handler) {
+      if (!this.listeners_)
+        this.listeners_ = Object.create(null);
+      if (!(type in this.listeners_)) {
+        this.listeners_[type] = [handler];
+      } else {
+        var handlers = this.listeners_[type];
+        if (handlers.indexOf(handler) < 0)
+          handlers.push(handler);
+      }
+    },
+
+    /**
+     * Removes an event listener from the target.
+     * @param {string} type The name of the event.
+     * @param {!Function|{handleEvent:Function}} handler The handler for the
+     *     event.
+     */
+    removeEventListener: function(type, handler) {
+      if (!this.listeners_)
+        return;
+      if (type in this.listeners_) {
+        var handlers = this.listeners_[type];
+        var index = handlers.indexOf(handler);
+        if (index >= 0) {
+          // Clean up if this was the last listener.
+          if (handlers.length == 1)
+            delete this.listeners_[type];
+          else
+            handlers.splice(index, 1);
+        }
+      }
+    },
+
+    /**
+     * Dispatches an event and calls all the listeners that are listening to
+     * the type of the event.
+     * @param {!cr.event.Event} event The event to dispatch.
+     * @return {boolean} Whether the default action was prevented. If someone
+     *     calls preventDefault on the event object then this returns false.
+     */
+    dispatchEvent: function(event) {
+      if (!this.listeners_)
+        return true;
+
+      // Since we are using DOM Event objects we need to override some of the
+      // properties and methods so that we can emulate this correctly.
+      var self = this;
+      event.__defineGetter__('target', function() {
+        return self;
+      });
+      event.preventDefault = function() {
+        this.returnValue = false;
+      };
+
+      var type = event.type;
+      var prevented = 0;
+      if (type in this.listeners_) {
+        // Clone to prevent removal during dispatch
+        var handlers = this.listeners_[type].concat();
+        for (var i = 0, handler; handler = handlers[i]; i++) {
+          if (handler.handleEvent)
+            prevented |= handler.handleEvent.call(handler, event) === false;
+          else
+            prevented |= handler.call(this, event) === false;
+        }
+      }
+
+      return !prevented && event.returnValue;
+    }
+  };
+
+  // Export
+  return {
+    EventTarget: EventTarget
+  };
+});