Bug 1133493: add e10s-friendly API to fetch a tab's outer window ID. r=florian,Standard8

browser/base/content/content.js

@@ -931,6 +931,13 @@ ContentWebRTC.init();
 addMessageListener("webrtc:Allow", ContentWebRTC);
 addMessageListener("webrtc:Deny", ContentWebRTC);
 addMessageListener("webrtc:StopSharing", ContentWebRTC);
+addMessageListener("webrtc:StartBrowserSharing", () => {
+  let windowID = content.QueryInterface(Ci.nsIInterfaceRequestor)
+                        .getInterface(Ci.nsIDOMWindowUtils).outerWindowID;
+  sendAsyncMessage("webrtc:response:StartBrowserSharing", {
+    windowID: windowID
+  });
+});
 
 function gKeywordURIFixup(fixupInfo) {
   fixupInfo.QueryInterface(Ci.nsIURIFixupInfo);

browser/components/loop/MozLoopAPI.jsm

@@ -257,6 +257,30 @@ function injectLoopAPI(targetWindow) {
       }
     },
 
+    getActiveTabWindowId: {
+      enumerable: true,
+      writable: true,
+      value: function(callback) {
+        let win = Services.wm.getMostRecentWindow("navigator:browser");
+        let browser = win && win.gBrowser.selectedTab.linkedBrowser;
+        if (!win || !browser) {
+          // This may happen when an undocked conversation window is the only
+          // window left.
+          let err = new Error("No tabs available to share.");
+          MozLoopService.log.error(err);
+          callback(cloneValueInto(err, targetWindow));
+          return;
+        }
+
+        let mm = browser.messageManager;
+        mm.addMessageListener("webrtc:response:StartBrowserSharing", function listener(message) {
+          mm.removeMessageListener("webrtc:response:StartBrowserSharing", listener);
+          callback(null, message.data.windowID);
+        });
+        mm.sendAsyncMessage("webrtc:StartBrowserSharing");
+      }
+    },
+
     /**
      * Returns the window data for a specific conversation window id.
      *

browser/components/loop/test/mochitest/browser.ini

@@ -21,5 +21,6 @@ skip-if = e10s
 skip-if = buildapp == 'mulet'
 [browser_toolbarbutton.js]
 [browser_mozLoop_pluralStrings.js]
+[browser_mozLoop_tabSharing.js]
 [browser_mozLoop_telemetry.js]
 skip-if = e10s

browser/components/loop/test/mochitest/browser_mozLoop_tabSharing.js

@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * This is an integration test to make sure that passing window IDs is working as
+ * expected, with or without e10s enabled - rather than just testing MozLoopAPI
+ * alone.
+ */
+
+const {injectLoopAPI} = Cu.import("resource:///modules/loop/MozLoopAPI.jsm");
+gMozLoopAPI = injectLoopAPI({});
+
+let promiseTabWindowId = function() {
+  return new Promise(resolve => {
+    gMozLoopAPI.getActiveTabWindowId((err, windowId) => {
+      Assert.equal(null, err, "No error should've occurred.");
+      Assert.equal(typeof windowId, "number", "We should have a window ID");
+      resolve(windowId);
+    });
+  });
+};
+
+add_task(function* test_windowIdFetch_simple() {
+  Assert.ok(gMozLoopAPI, "mozLoop should exist");
+
+  yield promiseTabWindowId();
+});
+
+add_task(function* test_windowIdFetch_multipleTabs() {
+  let previousTab = gBrowser.selectedTab;
+  let previousTabId = yield promiseTabWindowId();
+
+  let tab = gBrowser.selectedTab = gBrowser.addTab();
+  yield promiseTabLoadEvent(tab, "about:mozilla");
+  let tabId = yield promiseTabWindowId();
+  Assert.ok(tabId !== previousTabId, "Tab contentWindow IDs shouldn't be the same");
+  gBrowser.removeTab(tab);
+
+  tabId = yield promiseTabWindowId();
+  Assert.equal(previousTabId, tabId, "Window IDs should be back to what they were");
+});

browser/components/loop/test/mochitest/head.js

@@ -176,6 +176,50 @@ function promiseOAuthGetRegistration(baseURL) {
   });
 }
 
+/**
+ * Waits for a load (or custom) event to finish in a given tab. If provided
+ * load an uri into the tab.
+ *
+ * @param tab
+ *        The tab to load into.
+ * @param [optional] url
+ *        The url to load, or the current url.
+ * @param [optional] event
+ *        The load event type to wait for.  Defaults to "load".
+ * @return {Promise} resolved when the event is handled.
+ * @resolves to the received event
+ * @rejects if a valid load event is not received within a meaningful interval
+ */
+function promiseTabLoadEvent(tab, url, eventType="load") {
+  return new Promise((resolve, reject) => {
+    info("Wait tab event: " + eventType);
+
+    function handle(event) {
+      if (event.originalTarget != tab.linkedBrowser.contentDocument ||
+          event.target.location.href == "about:blank" ||
+          (url && event.target.location.href != url)) {
+        info("Skipping spurious '" + eventType + "'' event" +
+             " for " + event.target.location.href);
+        return;
+      }
+      clearTimeout(timeout);
+      tab.linkedBrowser.removeEventListener(eventType, handle, true);
+      info("Tab event received: " + eventType);
+      resolve(event);
+    }
+
+    let timeout = setTimeout(() => {
+      if (tab.linkedBrowser)
+        tab.linkedBrowser.removeEventListener(eventType, handle, true);
+      reject(new Error("Timed out while waiting for a '" + eventType + "'' event"));
+    }, 30000);
+
+    tab.linkedBrowser.addEventListener(eventType, handle, true, true);
+    if (url)
+      tab.linkedBrowser.loadURI(url);
+  });
+}
+
 function getLoopString(stringID) {
   return MozLoopServiceInternal.localizedStrings.get(stringID);
 }