DevTools: Add support for adding source map to a script from the DevTools window.

Source/devtools/front_end/sources/AddSourceMapURLDialog.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.DialogDelegate}
+ * @param {function(string)} callback
+ */
+WebInspector.AddSourceMapURLDialog = function(callback)
+{
+    WebInspector.DialogDelegate.call(this);
+
+    this.element = document.createElementWithClass("div", "go-to-line-dialog");
+    this.element.createChild("label").textContent = WebInspector.UIString("Source map URL: ");
+
+    this._input = this.element.createChild("input");
+    this._input.setAttribute("type", "text");
+
+    this._callback = callback;
+}
+
+/**
+ * @param {!Element} element
+ * @param {function(string)} callback
+ */
+WebInspector.AddSourceMapURLDialog.show = function(element, callback)
+{
+    WebInspector.Dialog.show(element, new WebInspector.AddSourceMapURLDialog(callback));
+}
+
+WebInspector.AddSourceMapURLDialog.prototype = {
+    focus: function()
+    {
+        WebInspector.setCurrentFocusElement(this._input);
+        this._input.select();
+    },
+
+    onEnter: function()
+    {
+        var value = this._input.value;
+        this._callback(value);
+    },
+
+    __proto__: WebInspector.DialogDelegate.prototype
+}