Bug 1320306 - Implement sessions.onChanged WebExtensions API, r=aswan

MozReview-Commit-ID: 14si74CKswB

--HG--
extra : rebase_source : 1090330364fa8c1bad79f2127dd15b6b5ec6cfaf

browser/components/extensions/ext-sessions.js

@@ -5,11 +5,14 @@
 Cu.import("resource://gre/modules/ExtensionUtils.jsm");
 var {
   promiseObserved,
+  SingletonEventManager,
 } = ExtensionUtils;
 
 XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
                                   "resource:///modules/sessionstore/SessionStore.jsm");
 
+const ssOnChangedTopic = "sessionstore-closed-objects-changed";
+
 function getRecentlyClosed(maxResults, extension) {
   let recentlyClosed = [];
 
@@ -87,6 +90,33 @@ extensions.registerSchemaAPI("sessions", "addon_parent", context => {
         }
         return createSession(session, extension, closedId);
       },
+      onChanged: new SingletonEventManager(context, "sessions.onChanged", fire => {
+        let listenerCount = 0;
+
+        let observer = {
+          observe: function() {
+            this.emit("changed");
+          },
+        };
+        EventEmitter.decorate(observer);
+
+        let listener = (event) => {
+          context.runSafe(fire);
+        };
+
+        observer.on("changed", listener);
+        listenerCount++;
+        if (listenerCount == 1) {
+          Services.obs.addObserver(observer, ssOnChangedTopic, false);
+        }
+        return () => {
+          observer.off("changed", listener);
+          listenerCount -= 1;
+          if (!listenerCount) {
+            Services.obs.removeObserver(observer, ssOnChangedTopic);
+          }
+        };
+      }).api(),
     },
   };
 });

browser/components/extensions/schemas/sessions.json

@@ -131,7 +131,6 @@
     "events": [
       {
         "name": "onChanged",
-        "unsupported": true,
         "description": "Fired when recently closed tabs and/or windows are changed. This event does not monitor synced sessions changes.",
         "type": "function"
       }

browser/components/extensions/test/browser/browser_ext_sessions_restore.js

@@ -6,9 +6,16 @@ SimpleTest.requestCompleteLog();
 
 XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
                                   "resource:///modules/sessionstore/SessionStore.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "TabStateFlusher",
+                                  "resource:///modules/sessionstore/TabStateFlusher.jsm");
 
 add_task(function* test_sessions_restore() {
   function background() {
+    let notificationCount = 0;
+    browser.sessions.onChanged.addListener(() => {
+      notificationCount++;
+      browser.test.sendMessage("notificationCount", notificationCount);
+    });
     browser.test.onMessage.addListener((msg, data) => {
       if (msg == "check-sessions") {
         browser.sessions.getRecentlyClosed().then(recentlyClosed => {
@@ -31,6 +38,7 @@ add_task(function* test_sessions_restore() {
         );
       }
     });
+    browser.test.sendMessage("ready");
   }
 
   let extension = ExtensionTestUtils.loadExtension({
@@ -40,6 +48,11 @@ add_task(function* test_sessions_restore() {
     background,
   });
 
+  function* assertNotificationCount(expected) {
+    let notificationCount = yield extension.awaitMessage("notificationCount");
+    is(notificationCount, expected, "the expected number of notifications was fired");
+  }
+
   yield extension.startup();
 
   let {Management: {global: {WindowManager, TabManager}}} = Cu.import("resource://gre/modules/Extension.jsm", {});
@@ -50,6 +63,8 @@ add_task(function* test_sessions_restore() {
     is(tabState.entries[0].url, expectedUrl, "restored tab has the expected url");
   }
 
+  yield extension.awaitMessage("ready");
+
   let win = yield BrowserTestUtils.openNewBrowserWindow();
   yield BrowserTestUtils.loadURI(win.gBrowser.selectedBrowser, "about:config");
   yield BrowserTestUtils.browserLoaded(win.gBrowser.selectedBrowser);
@@ -57,6 +72,7 @@ add_task(function* test_sessions_restore() {
     yield BrowserTestUtils.openNewForegroundTab(win.gBrowser, url);
   }
   yield BrowserTestUtils.closeWindow(win);
+  yield assertNotificationCount(1);
 
   extension.sendMessage("check-sessions");
   let recentlyClosed = yield extension.awaitMessage("recentlyClosed");
@@ -66,6 +82,7 @@ add_task(function* test_sessions_restore() {
 
   // Restore the window.
   extension.sendMessage("restore");
+  yield assertNotificationCount(2);
   let restored = yield extension.awaitMessage("restored");
 
   is(restored.length, 1, "restore returned the expected number of sessions");
@@ -77,11 +94,13 @@ add_task(function* test_sessions_restore() {
   // Close the window again.
   let window = WindowManager.getWindow(restored[0].window.id);
   yield BrowserTestUtils.closeWindow(window);
+  yield assertNotificationCount(3);
 
   // Restore the window using the sessionId.
   extension.sendMessage("check-sessions");
   recentlyClosed = yield extension.awaitMessage("recentlyClosed");
   extension.sendMessage("restore", recentlyClosed[0].window.sessionId);
+  yield assertNotificationCount(4);
   restored = yield extension.awaitMessage("restored");
 
   is(restored.length, 1, "restore returned the expected number of sessions");
@@ -93,13 +112,18 @@ add_task(function* test_sessions_restore() {
   // Close the window again.
   window = WindowManager.getWindow(restored[0].window.id);
   yield BrowserTestUtils.closeWindow(window);
+  // notificationCount = yield extension.awaitMessage("notificationCount");
+  yield assertNotificationCount(5);
 
   // Open and close a tab.
   let tab = yield BrowserTestUtils.openNewForegroundTab(gBrowser, "about:robots");
+  yield TabStateFlusher.flush(tab.linkedBrowser);
   yield BrowserTestUtils.removeTab(tab);
+  yield assertNotificationCount(6);
 
   // Restore the most recently closed item.
   extension.sendMessage("restore");
+  yield assertNotificationCount(7);
   restored = yield extension.awaitMessage("restored");
 
   is(restored.length, 1, "restore returned the expected number of sessions");
@@ -110,11 +134,13 @@ add_task(function* test_sessions_restore() {
   // Close the tab again.
   let realTab = TabManager.getTab(tab.id);
   yield BrowserTestUtils.removeTab(realTab);
+  yield assertNotificationCount(8);
 
   // Restore the tab using the sessionId.
   extension.sendMessage("check-sessions");
   recentlyClosed = yield extension.awaitMessage("recentlyClosed");
   extension.sendMessage("restore", recentlyClosed[0].tab.sessionId);
+  yield assertNotificationCount(9);
   restored = yield extension.awaitMessage("restored");
 
   is(restored.length, 1, "restore returned the expected number of sessions");
@@ -125,6 +151,7 @@ add_task(function* test_sessions_restore() {
   // Close the tab again.
   realTab = TabManager.getTab(tab.id);
   yield BrowserTestUtils.removeTab(realTab);
+  yield assertNotificationCount(10);
 
   // Try to restore something with an invalid sessionId.
   extension.sendMessage("restore-reject");