Revert "Remove WebIDE devtools component."

This reverts commit 8c1500707f.

# Conflicts:
#	application/basilisk/components/customizableui/CustomizableUI.jsm

devtools/client/projecteditor/lib/plugins/app-manager/app-project-editor.js

@@ -0,0 +1,56 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
+/* 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/. */
+
+const { Cu } = require("chrome");
+const { Class } = require("sdk/core/heritage");
+const promise = require("promise");
+const { ItchEditor } = require("devtools/client/projecteditor/lib/editors");
+
+var AppProjectEditor = Class({
+  extends: ItchEditor,
+
+  hidesToolbar: true,
+
+  initialize: function (host) {
+    ItchEditor.prototype.initialize.apply(this, arguments);
+    this.appended = promise.resolve();
+    this.host = host;
+    this.label = "app-manager";
+  },
+
+  destroy: function () {
+    this.elt.remove();
+    this.elt = null;
+  },
+
+  load: function (resource) {
+    let {appManagerOpts} = this.host.project;
+
+    // Only load the frame the first time it is selected
+    if (!this.iframe || this.iframe.getAttribute("src") !== appManagerOpts.projectOverviewURL) {
+
+      this.elt.textContent = "";
+      let iframe = this.iframe = this.elt.ownerDocument.createElement("iframe");
+      let iframeLoaded = this.iframeLoaded = promise.defer();
+
+      iframe.addEventListener("load", function onLoad() {
+        iframe.removeEventListener("load", onLoad);
+        iframeLoaded.resolve();
+      });
+
+      iframe.setAttribute("flex", "1");
+      iframe.setAttribute("src", appManagerOpts.projectOverviewURL);
+      this.elt.appendChild(iframe);
+
+    }
+
+    promise.all([this.iframeLoaded.promise, this.appended]).then(() => {
+      this.emit("load");
+    });
+  }
+});
+
+exports.AppProjectEditor = AppProjectEditor;