diff -r 000000000000 -r 6474c204b198 browser/devtools/styleeditor/StyleEditorUtil.jsm
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/styleeditor/StyleEditorUtil.jsm	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,228 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = [
+  "_",
+  "assert",
+  "log",
+  "text",
+  "wire",
+  "showFilePicker"
+];
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+const PROPERTIES_URL = "chrome://browser/locale/devtools/styleeditor.properties";
+
+const console = Services.console;
+const gStringBundle = Services.strings.createBundle(PROPERTIES_URL);
+
+
+/**
+ * Returns a localized string with the given key name from the string bundle.
+ *
+ * @param aName
+ * @param ...rest
+ *        Optional arguments to format in the string.
+ * @return string
+ */
+this._ = function _(aName)
+{
+
+  if (arguments.length == 1) {
+    return gStringBundle.GetStringFromName(aName);
+  }
+  let rest = Array.prototype.slice.call(arguments, 1);
+  return gStringBundle.formatStringFromName(aName, rest, rest.length);
+}
+
+/**
+ * Assert an expression is true or throw if false.
+ *
+ * @param aExpression
+ * @param aMessage
+ *        Optional message.
+ * @return aExpression
+ */
+this.assert = function assert(aExpression, aMessage)
+{
+  if (!!!(aExpression)) {
+    let msg = aMessage ? "ASSERTION FAILURE:" + aMessage : "ASSERTION FAILURE";
+    log(msg);
+    throw new Error(msg);
+  }
+  return aExpression;
+}
+
+/**
+ * Retrieve or set the text content of an element.
+ *
+ * @param DOMElement aRoot
+ *        The element to use for querySelector.
+ * @param string aSelector
+ *        Selector string for the element to get/set the text content.
+ * @param string aText
+ *        Optional text to set.
+ * @return string
+ *         Text content of matching element or null if there were no element
+ *         matching aSelector.
+ */
+this.text = function text(aRoot, aSelector, aText)
+{
+  let element = aRoot.querySelector(aSelector);
+  if (!element) {
+    return null;
+  }
+
+  if (aText === undefined) {
+    return element.textContent;
+  }
+  element.textContent = aText;
+  return aText;
+}
+
+/**
+ * Iterates _own_ properties of an object.
+ *
+ * @param aObject
+ *        The object to iterate.
+ * @param function aCallback(aKey, aValue)
+ */
+function forEach(aObject, aCallback)
+{
+  for (let key in aObject) {
+    if (aObject.hasOwnProperty(key)) {
+      aCallback(key, aObject[key]);
+    }
+  }
+}
+
+/**
+ * Log a message to the console.
+ *
+ * @param ...rest
+ *        One or multiple arguments to log.
+ *        If multiple arguments are given, they will be joined by " " in the log.
+ */
+this.log = function log()
+{
+  console.logStringMessage(Array.prototype.slice.call(arguments).join(" "));
+}
+
+/**
+ * Wire up element(s) matching selector with attributes, event listeners, etc.
+ *
+ * @param DOMElement aRoot
+ *        The element to use for querySelectorAll.
+ *        Can be null if aSelector is a DOMElement.
+ * @param string|DOMElement aSelectorOrElement
+ *        Selector string or DOMElement for the element(s) to wire up.
+ * @param object aDescriptor
+ *        An object describing how to wire matching selector, supported properties
+ *        are "events" and "attributes" taking objects themselves.
+ *        Each key of properties above represents the name of the event or
+ *        attribute, with the value being a function used as an event handler or
+ *        string to use as attribute value.
+ *        If aDescriptor is a function, the argument is equivalent to :
+ *        {events: {'click': aDescriptor}}
+ */
+this.wire = function wire(aRoot, aSelectorOrElement, aDescriptor)
+{
+  let matches;
+  if (typeof(aSelectorOrElement) == "string") { // selector
+    matches = aRoot.querySelectorAll(aSelectorOrElement);
+    if (!matches.length) {
+      return;
+    }
+  } else {
+    matches = [aSelectorOrElement]; // element
+  }
+
+  if (typeof(aDescriptor) == "function") {
+    aDescriptor = {events: {click: aDescriptor}};
+  }
+
+  for (let i = 0; i < matches.length; i++) {
+    let element = matches[i];
+    forEach(aDescriptor.events, function (aName, aHandler) {
+      element.addEventListener(aName, aHandler, false);
+    });
+    forEach(aDescriptor.attributes, element.setAttribute);
+  }
+}
+
+/**
+ * Show file picker and return the file user selected.
+ *
+ * @param mixed file
+ *        Optional nsIFile or string representing the filename to auto-select.
+ * @param boolean toSave
+ *        If true, the user is selecting a filename to save.
+ * @param nsIWindow parentWindow
+ *        Optional parent window. If null the parent window of the file picker
+ *        will be the window of the attached input element.
+ * @param callback
+ *        The callback method, which will be called passing in the selected
+ *        file or null if the user did not pick one.
+ * @param AString suggestedFilename
+ *        The suggested filename when toSave is true.
+ */
+this.showFilePicker = function showFilePicker(path, toSave, parentWindow,
+                                              callback, suggestedFilename)
+{
+  if (typeof(path) == "string") {
+    try {
+      if (Services.io.extractScheme(path) == "file") {
+        let uri = Services.io.newURI(path, null, null);
+        let file = uri.QueryInterface(Ci.nsIFileURL).file;
+        callback(file);
+        return;
+      }
+    } catch (ex) {
+      callback(null);
+      return;
+    }
+    try {
+      let file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);
+      file.initWithPath(path);
+      callback(file);
+      return;
+    } catch (ex) {
+      callback(null);
+      return;
+    }
+  }
+  if (path) { // "path" is an nsIFile
+    callback(path);
+    return;
+  }
+
+  let fp = Cc["@mozilla.org/filepicker;1"].createInstance(Ci.nsIFilePicker);
+  let mode = toSave ? fp.modeSave : fp.modeOpen;
+  let key = toSave ? "saveStyleSheet" : "importStyleSheet";
+  let fpCallback = function(result) {
+    if (result == Ci.nsIFilePicker.returnCancel) {
+      callback(null);
+    } else {
+      callback(fp.file);
+    }
+  };
+
+  if (toSave && suggestedFilename) {
+    fp.defaultString = suggestedFilename;
+  }
+
+  fp.init(parentWindow, _(key + ".title"), mode);
+  fp.appendFilters(_(key + ".filter"), "*.css");
+  fp.appendFilters(fp.filterAll);
+  fp.open(fpCallback);
+  return;
+}