--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -1290,18 +1290,16 @@ pref("shumway.disabled", true);
 pref("image.mem.max_decoded_image_kb", 256000);
 
 // Default social providers
 pref("social.manifest.facebook", "{\"origin\":\"https://www.facebook.com\",\"name\":\"Facebook Messenger\",\"workerURL\":\"https://www.facebook.com/desktop/fbdesktop2/socialfox/fbworker.js.php\",\"shareURL\":\"https://www.facebook.com/sharer/sharer.php?u=%{url}\",\"iconURL\":\"data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8%2F9hAAAAX0lEQVQ4jWP4%2F%2F8%2FAyUYTFhHzjgDxP9JxGeQDSBVMxgTbUBCxer%2Fr999%2BQ8DJBuArJksA9A10s8AXIBoA0B%2BR%2FY%2FjD%2BEwoBoA1yT5v3PbdmCE8MAshhID%2FUMoDgzUYIBj0Cgi7ar4coAAAAASUVORK5CYII%3D\",\"sidebarURL\":\"https://www.facebook.com/desktop/fbdesktop2/?socialfox=true\",\"icon32URL\":\"data:image/png;base64,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\", \"icon64URL\":\"data:image/png;base64,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\", \"description\":\"Keep up with friends wherever you go on the web.\",\"author\":\"Facebook\",\"homepageURL\":\"https://www.facebook.com/about/messenger-for-firefox\",\"builtin\":\"true\"}");
 
 pref("social.sidebar.open", true);
 pref("social.sidebar.unload_timeout_ms", 10000);
 
-pref("social.allowMultipleWorkers", true);
-
 pref("dom.identity.enabled", false);
 
 // Turn on the CSP 1.0 parser for Content Security Policy headers
 pref("security.csp.speccompliant", true);
 
 // Block insecure active content on https pages
 pref("security.mixed_content.block_active_content", true);
 

--- a/browser/base/content/test/social/browser_social_chatwindow.js
+++ b/browser/base/content/test/social/browser_social_chatwindow.js
@@ -46,37 +46,42 @@ function openChat(provider, callback) {
 
 function waitPrefChange(cb) {
   Services.prefs.addObserver("social.enabled", function prefObserver(subject, topic, data) {
     Services.prefs.removeObserver("social.enabled", prefObserver);
     executeSoon(cb);
   }, false);
 }
 
+function setWorkerMode(multiple, cb) {
+  waitPrefChange(function() {
+    if (multiple)
+      Services.prefs.setBoolPref("social.allowMultipleWorkers", true);
+    else
+      Services.prefs.clearUserPref("social.allowMultipleWorkers");
+    waitPrefChange(cb);
+    Social.enabled = true;
+  });
+  Social.enabled = false;
+}
+
 function test() {
   requestLongerTimeout(2); // only debug builds seem to need more time...
   waitForExplicitFinish();
 
   let oldwidth = window.outerWidth; // we futz with these, so we restore them
   let oldleft = window.screenX;
   window.moveTo(0, window.screenY)
   let postSubTest = function(cb) {
     let chats = document.getElementById("pinnedchats");
     ok(chats.children.length == 0, "no chatty children left behind");
     cb();
   };
-  // always run chat tests with multiple workers.
-  Services.prefs.setBoolPref("social.allowMultipleWorkers", true);
   runSocialTestWithProvider(manifests, function (finishcb) {
-    ok(Social.enabled, "Social is enabled");
-    ok(Social.providers[0].getWorkerPort(), "provider 0 has port");
-    ok(Social.providers[1].getWorkerPort(), "provider 1 has port");
-    ok(Social.providers[2].getWorkerPort(), "provider 2 has port");
     runSocialTests(tests, undefined, postSubTest, function() {
-      Services.prefs.clearUserPref("social.allowMultipleWorkers");
       window.moveTo(oldleft, window.screenY)
       window.resizeTo(oldwidth, window.outerHeight);
       finishcb();
     });
   });
 }
 
 var tests = {
@@ -507,41 +512,40 @@ var tests = {
             });
             window.focus();
           });
         });
       })
     });
   },
   testMultipleProviderChat: function(next) {
-    // test incomming chats from all providers
-    openChat(Social.providers[0], function() {
-      openChat(Social.providers[1], function() {
-        openChat(Social.providers[2], function() {
-          let chats = document.getElementById("pinnedchats");
-          waitForCondition(function() chats.children.length == Social.providers.length,
-            function() {
-              ok(true, "one chat window per provider opened");
-              // test logout of a single provider
-              let provider = Social.providers[2];
-              let port = provider.getWorkerPort();
-              port.postMessage({topic: "test-logout"});
-              waitForCondition(function() chats.children.length == Social.providers.length - 1,
-                function() {
-                  chats.removeAll();
-                  waitForCondition(function() chats.children.length == 0,
-                                   function() {
-                                    ok(!chats.selectedChat, "multiprovider chats are all closed");
-                                    port.close();
-                                    next();
-                                   },
-                                   "chat windows didn't close");
-                },
-                "chat window didn't close");
-            }, "chat windows did not open");
+    // while pref'd off, we need to set the worker mode to multiple providers
+    setWorkerMode(true, function() {
+      // test incomming chats from all providers
+      openChat(Social.providers[0], function() {
+        openChat(Social.providers[1], function() {
+          openChat(Social.providers[2], function() {
+            let chats = document.getElementById("pinnedchats");
+            waitForCondition(function() chats.children.length == Social.providers.length,
+              function() {
+                ok(true, "one chat window per provider opened");
+                // test logout of a single provider
+                let provider = Social.providers[0];
+                let port = provider.getWorkerPort();
+                port.postMessage({topic: "test-logout"});
+                waitForCondition(function() chats.children.length == Social.providers.length - 1,
+                  function() {
+                    port.close();
+                    chats.removeAll();
+                    ok(!chats.selectedChat, "chats are all closed");
+                    setWorkerMode(false, next);
+                  },
+                  "chat window didn't close");
+              }, "chat windows did not open");
+          });
         });
       });
     });
   },
 
   // XXX - note this must be the last test until we restore the login state
   // between tests...
   testCloseOnLogout: function(next) {
@@ -569,15 +573,11 @@ var tests = {
           } else {
             // open a second chat window
             opened = true;
             port.postMessage({topic: "test-worker-chat", data: chatUrl+"?id=1"});
           }
           break;
       }
     }
-    // make sure a user profile is set for this provider as chat windows are
-    // only closed on *change* of the profile data rather than merely setting
-    // profile data.
-    port.postMessage({topic: "test-set-profile"});
     port.postMessage({topic: "test-init"});
   }
 }

--- a/browser/base/content/test/social/browser_social_flyout.js
+++ b/browser/base/content/test/social/browser_social_flyout.js
@@ -108,27 +108,25 @@ var tests = {
     ok(port, "provider has a port");
     port.onmessage = function (e) {
       let topic = e.data.topic;
       switch (topic) {
         case "test-init-done":
           port.postMessage({topic: "test-flyout-open"});
           break;
         case "got-flyout-visibility":
-          if (e.data.result != "shown")
-            return;
           let iframe = panel.firstChild;
           iframe.contentDocument.addEventListener("SocialTest-DoneCloseSelf", function _doneHandler() {
             iframe.contentDocument.removeEventListener("SocialTest-DoneCloseSelf", _doneHandler, false);
-            port.close();
             is(panel.state, "closed", "flyout should have closed itself");
             Services.prefs.setBoolPref(ALLOW_SCRIPTS_TO_CLOSE_PREF, oldAllowScriptsToClose);
             next();
           }, false);
           is(panel.state, "open", "flyout should be open");
+          port.close(); // so we don't get the -visibility message as it hides...
           SocialFlyout.dispatchPanelEvent("socialTest-CloseSelf");
           break;
       }
     }
     port.postMessage({topic: "test-init"});
   },
 
   testCloseOnLinkTraversal: function(next) {

--- a/browser/base/content/test/social/social_worker.js
+++ b/browser/base/content/test/social/social_worker.js
@@ -79,34 +79,32 @@ onconnect = function(e) {
       case "test-worker-chat":
         apiPort.postMessage({topic: "social.request-chat", data: event.data.data });
         break;
       case "social.initialize":
         // This is the workerAPI port, respond and set up a notification icon.
         // For multiprovider tests, we support acting like different providers
         // based on the domain we load from.
         apiPort = port;
-        // purposely fall through and set the profile on initialization
-      case "test-set-profile":
         let profile;
         if (location.href.indexOf("https://test1.example.com") == 0) {
           profile = {
             portrait: "https://test1.example.com/portrait.jpg",
             userName: "tester",
             displayName: "Test1 User",
           };
         } else {
           profile = {
             portrait: "https://example.com/portrait.jpg",
             userName: "trickster",
             displayName: "Kuma Lisa",
             profileURL: "http://en.wikipedia.org/wiki/Kuma_Lisa"
           };
         }
-        apiPort.postMessage({topic: "social.user-profile", data: profile});
+        port.postMessage({topic: "social.user-profile", data: profile});
         break;
       case "test-ambient-notification":
         apiPort.postMessage({topic: "social.ambient-notification", data: event.data.data});
         break;
       case "test-isVisible":
         sidebarPort.postMessage({topic: "test-isVisible"});
         break;
       case "test-isVisible-response":

--- a/browser/modules/Social.jsm
+++ b/browser/modules/Social.jsm
@@ -90,17 +90,18 @@ function promiseGetAnnotation(aURI) {
 
 this.Social = {
   initialized: false,
   lastEventReceived: 0,
   providers: [],
   _disabledForSafeMode: false,
 
   get allowMultipleWorkers() {
-    return Services.prefs.getBoolPref("social.allowMultipleWorkers");
+    return Services.prefs.prefHasUserValue("social.allowMultipleWorkers") &&
+           Services.prefs.getBoolPref("social.allowMultipleWorkers");
   },
 
   get _currentProviderPref() {
     try {
       return Services.prefs.getComplexValue("social.provider.current",
                                             Ci.nsISupportsString).data;
     } catch (ex) {}
     return null;
@@ -135,17 +136,16 @@ this.Social = {
 
     if (this._provider) {
       this._provider.enabled = true;
       this._currentProviderPref = this._provider.origin;
     }
     let enabled = !!provider;
     if (enabled != SocialService.enabled) {
       SocialService.enabled = enabled;
-      this._updateWorkerState(enabled);
     }
 
     let origin = this._provider && this._provider.origin;
     Services.obs.notifyObservers(null, "social:provider-set", origin);
   },
 
   get defaultProvider() {
     if (this.providers.length == 0)

--- a/toolkit/components/social/FrameWorker.jsm
+++ b/toolkit/components/social/FrameWorker.jsm
@@ -194,23 +194,25 @@ function makeRemoteBrowser() {
   // Create a HTML iframe with a chrome URL, then this can host the browser.
   let iframe = hiddenDoc.createElementNS(HTML_NS, "iframe");
   iframe.setAttribute("src", "chrome://global/content/mozilla.xhtml");
   iframe.addEventListener("load", function onLoad() {
     iframe.removeEventListener("load", onLoad, true);
     let browser = iframe.contentDocument.createElementNS(XUL_NS, "browser");
     browser.setAttribute("type", "content");
     browser.setAttribute("disableglobalhistory", "true");
+    let remote;
     // for now we use the same preference that enabled multiple workers - the
     // idea is that there is no point in having people help test multiple
     // "old" frameworkers - so anyone who wants multiple workers is forced to
     // help us test remote frameworkers too.
-    if (Services.prefs.getBoolPref("social.allowMultipleWorkers"))
+    if (Services.prefs.prefHasUserValue("social.allowMultipleWorkers") &&
+        Services.prefs.getBoolPref("social.allowMultipleWorkers")) {
       browser.setAttribute("remote", "true");
-
+    }
     iframe.contentDocument.documentElement.appendChild(browser);
     deferred.resolve(browser);
   }, true);
   hiddenDoc.documentElement.appendChild(iframe);
   return deferred.promise;
 }
 
 function notifyWorkerError(origin) {

--- a/toolkit/components/social/test/browser/browser_SocialProvider.js
+++ b/toolkit/components/social/test/browser/browser_SocialProvider.js
@@ -57,17 +57,17 @@ let tests = {
     // add another provider, test both workers
     let manifest = {
       origin: 'http://test2.example.com',
       name: "Example Provider 2",
       workerURL: "http://test2.example.com/browser/toolkit/components/social/test/browser/worker_social.js"
     };
     SocialService.addProvider(manifest, function (provider2) {
       ok(provider.enabled, "provider is initially enabled");
-      is(provider2.enabled, Services.prefs.getBoolPref("social.allowMultipleWorkers"), "provider2 is enabled status is correct");
+      ok(!provider2.enabled, "provider2 is not initially enabled");
       provider2.enabled = true;
       let port = provider.getWorkerPort();
       let port2 = provider2.getWorkerPort();
       ok(port, "have port for provider");
       ok(port2, "have port for provider2");
       port.onmessage = function(e) {
         if (e.data.topic == "test-initialization-complete") {
           ok(true, "first provider initialized");

--- a/toolkit/components/social/test/browser/browser_frameworker.js
+++ b/toolkit/components/social/test/browser/browser_frameworker.js
@@ -44,35 +44,29 @@ let tests = {
         worker.terminate();
         cbnext();
       }
     }
     worker.port.postMessage({topic: "ping"})
   },
 
   // when the client closes early but the worker tries to send anyway...
-  // XXX - disabled due to bug 919878 - we close the frameworker before the
-  // remote browser has completed initializing, leading to failures.  Given
-  // this can realistically only happen in this synthesized test environment,
-  // disabling just this test seems OK for now.
-/***
   testEarlyClose: function(cbnext) {
     let run = function() {
       onconnect = function(e) {
         let port = e.ports[0];
         port.postMessage({topic: "oh hai"});
       }
     }
 
     let worker = getFrameWorkerHandle(makeWorkerUrl(run), undefined, "testEarlyClose");
     worker.port.close();
     worker.terminate();
     cbnext();
   },
-***/
 
   // Check we do get a social.port-closing message as the port is closed.
   testPortClosingMessage: function(cbnext) {
     // We use 2 ports - we close the first and report success via the second.
     let run = function() {
       let firstPort, secondPort;
       onconnect = function(e) {
         let port = e.ports[0];