DevTools - style editor - StyleSheetsActor should use the parent tabActor to retrieve the list of windows and react to new/removed windows

https://github.com/MoonchildProductions/moebius/pull/124

devtools/client/styleeditor/test/browser.ini

@@ -60,6 +60,7 @@ support-files =
   !/devtools/client/shared/test/test-actor-registry.js
   !/devtools/client/shared/test/test-actor.js
 
+[browser_styleeditor_add_stylesheet.js]
 [browser_styleeditor_autocomplete.js]
 [browser_styleeditor_autocomplete-disabled.js]
 [browser_styleeditor_bom.js]

devtools/client/styleeditor/test/browser_styleeditor_add_stylesheet.js

@@ -0,0 +1,37 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that a newly-added style sheet shows up in the style editor.
+
+const TESTCASE_URI = TEST_BASE_HTTPS + "simple.html";
+
+add_task(function* () {
+  let { ui } = yield openStyleEditorForURL(TESTCASE_URI);
+
+  is(ui.editors.length, 2, "Two sheets present after load.");
+
+  // We have to wait for the length to change, because we might still
+  // be seeing events from the initial open.
+  let added = new Promise(resolve => {
+    let handler = () => {
+      if (ui.editors.length === 3) {
+        ui.off("editor-added", handler);
+        resolve();
+      }
+    };
+    ui.on("editor-added", handler);
+  });
+
+  info("Adding a style sheet");
+  yield ContentTask.spawn(gBrowser.selectedBrowser, null, () => {
+    let document = content.document;
+    const style = document.createElement("style");
+    style.appendChild(document.createTextNode("div { background: #f06; }"));
+    document.head.appendChild(style);
+  });
+  yield added;
+
+  is(ui.editors.length, 3, "Three sheets present after new style sheet");
+});

devtools/client/styleeditor/test/browser_styleeditor_import.js

@@ -18,7 +18,7 @@ const SOURCE = "body{background:red;}";
 add_task(function* () {
   let { panel, ui } = yield openStyleEditorForURL(TESTCASE_URI);
 
-  let added = ui.once("editor-added");
+  let added = ui.once("test:editor-updated");
   importSheet(ui, panel.panelWindow);
 
   info("Waiting for editor to be added for the imported sheet.");