DevTools: Implement console message logging through an extension

Source/devtools/front_end/common/MessageSink.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.
+
+/**
+ * @constructor
+ * @extends {WebInspector.Object}
+ */
+WebInspector.MessageSink = function()
+{
+    /** @type {!Array.<!WebInspector.MessageSink.Message>} */
+    this._messages = [];
+}
+
+/**
+ * @enum {string}
+ */
+WebInspector.MessageSink.Events = {
+    MessageAdded: "messageAdded"
+}
+
+/**
+ * @enum {string}
+ */
+WebInspector.MessageSink.MessageLevel = {
+    Log: "log",
+    Warning: "warning",
+    Error: "error"
+}
+
+/**
+ * @constructor
+ * @param {string} text
+ * @param {!WebInspector.MessageSink.MessageLevel} level
+ * @param {number} timestamp
+ * @param {boolean} show
+ */
+WebInspector.MessageSink.Message = function(text, level, timestamp, show)
+{
+    this.text = text;
+    this.level = level;
+    this.timestamp = (typeof timestamp === "number") ? timestamp : Date.now();
+    this.show = show;
+}
+
+WebInspector.MessageSink.prototype = {
+    /**
+     * @param {string} text
+     * @param {!WebInspector.MessageSink.MessageLevel=} level
+     * @param {boolean=} show
+     */
+    addMessage: function(text, level, show)
+    {
+        var message = new WebInspector.MessageSink.Message(text, level || WebInspector.MessageSink.MessageLevel.Log, Date.now(), show || false);
+        this._messages.push(message);
+        this.dispatchEventToListeners(WebInspector.MessageSink.Events.MessageAdded, message);
+    },
+
+    /**
+     * @param {string} text
+     * @param {boolean=} show
+     */
+    addErrorMessage: function(text, show)
+    {
+        this.addMessage(text, WebInspector.MessageSink.MessageLevel.Error, show);
+    },
+
+    /**
+     * @return {!Array.<!WebInspector.MessageSink.Message>}
+     */
+    messages: function()
+    {
+        return this._messages;
+    },
+
+    __proto__: WebInspector.Object.prototype
+}
+
+WebInspector.messageSink = new WebInspector.MessageSink();