--- a/accessible/generic/Accessible.cpp
+++ b/accessible/generic/Accessible.cpp
@@ -2158,22 +2158,23 @@ Accessible::RemoveChild(Accessible* aChi
   }
 
   return true;
 }
 
 void
 Accessible::MoveChild(uint32_t aNewIndex, Accessible* aChild)
 {
-  MOZ_ASSERT(aChild, "No child was given");
-  MOZ_ASSERT(aChild->mParent == this, "A child from different subtree was given");
-  MOZ_ASSERT(aChild->mIndexInParent != -1, "Unbound child was given");
-  MOZ_ASSERT(static_cast<uint32_t>(aChild->mIndexInParent) != aNewIndex,
+  MOZ_DIAGNOSTIC_ASSERT(aChild, "No child was given");
+  MOZ_DIAGNOSTIC_ASSERT(aChild->mParent == this, "A child from different subtree was given");
+  MOZ_DIAGNOSTIC_ASSERT(aChild->mIndexInParent != -1, "Unbound child was given");
+  MOZ_DIAGNOSTIC_ASSERT(aChild->mParent->GetChildAt(aChild->mIndexInParent) == aChild, "Wrong index in parent");
+  MOZ_DIAGNOSTIC_ASSERT(static_cast<uint32_t>(aChild->mIndexInParent) != aNewIndex,
              "No move, same index");
-  MOZ_ASSERT(aNewIndex <= mChildren.Length(), "Wrong new index was given");
+  MOZ_DIAGNOSTIC_ASSERT(aNewIndex <= mChildren.Length(), "Wrong new index was given");
 
   RefPtr<AccHideEvent> hideEvent = new AccHideEvent(aChild, false);
   if (mDoc->Controller()->QueueMutationEvent(hideEvent)) {
     aChild->SetHideEventTarget(true);
   }
 
   mEmbeddedObjCollector = nullptr;
   mChildren.RemoveElementAt(aChild->mIndexInParent);

--- a/browser/app/nsBrowserApp.cpp
+++ b/browser/app/nsBrowserApp.cpp
@@ -212,23 +212,26 @@ static int do_main(int argc, char* argv[
     // no -app flag so we use the compiled-in app data
     config.appData = &sAppData;
     config.appDataPath = kDesktopFolder;
   }
 
 #if defined(XP_WIN) && defined(MOZ_SANDBOX)
   sandbox::BrokerServices* brokerServices =
     sandboxing::GetInitializedBrokerServices();
+  sandboxing::PermissionsService* permissionsService =
+    sandboxing::GetPermissionsService();
 #if defined(MOZ_CONTENT_SANDBOX)
   if (!brokerServices) {
     Output("Couldn't initialize the broker services.\n");
     return 255;
   }
 #endif
   config.sandboxBrokerServices = brokerServices;
+  config.sandboxPermissionsService = permissionsService;
 #endif
 
 #ifdef LIBFUZZER
   if (getenv("LIBFUZZER"))
     gBootstrap->XRE_LibFuzzerSetDriver(fuzzer::FuzzerDriver);
 #endif
 
   return gBootstrap->XRE_main(argc, argv, config);

--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -455,48 +455,49 @@ const gStoragePressureObserver = {
 
     const BYTES_IN_GIGABYTE = 1073741824;
     const USAGE_THRESHOLD_BYTES = BYTES_IN_GIGABYTE *
       Services.prefs.getIntPref("browser.storageManager.pressureNotification.usageThresholdGB");
     let msg = "";
     let buttons = [];
     let usage = parseInt(data);
     let prefStrBundle = document.getElementById("bundle_preferences");
+    let brandShortName = document.getElementById("bundle_brand").getString("brandShortName");
     let notificationBox = document.getElementById("high-priority-global-notificationbox");
     buttons.push({
       label: prefStrBundle.getString("spaceAlert.learnMoreButton.label"),
       accessKey: prefStrBundle.getString("spaceAlert.learnMoreButton.accesskey"),
       callback(notificationBar, button) {
         let learnMoreURL = Services.urlFormatter.formatURLPref("app.support.baseURL") + "storage-permissions";
         gBrowser.selectedTab = gBrowser.addTab(learnMoreURL);
       }
     });
     if (usage < USAGE_THRESHOLD_BYTES) {
       // The firefox-used space < 5GB, then warn user to free some disk space.
       // This is because this usage is small and not the main cause for space issue.
       // In order to avoid the bad and wrong impression among users that
       // firefox eats disk space a lot, indicate users to clean up other disk space.
-      msg = prefStrBundle.getString("spaceAlert.under5GB.description");
+      msg = prefStrBundle.getFormattedString("spaceAlert.under5GB.message", [brandShortName]);
       buttons.push({
         label: prefStrBundle.getString("spaceAlert.under5GB.okButton.label"),
         accessKey: prefStrBundle.getString("spaceAlert.under5GB.okButton.accesskey"),
         callback() {}
       });
     } else {
       // The firefox-used space >= 5GB, then guide users to about:preferences
       // to clear some data stored on firefox by websites.
-      let descriptionStringID = "spaceAlert.over5GB.description";
+      let descriptionStringID = "spaceAlert.over5GB.message";
       let prefButtonLabelStringID = "spaceAlert.over5GB.prefButton.label";
       let prefButtonAccesskeyStringID = "spaceAlert.over5GB.prefButton.accesskey";
       if (AppConstants.platform == "win") {
-        descriptionStringID = "spaceAlert.over5GB.descriptionWin";
+        descriptionStringID = "spaceAlert.over5GB.messageWin";
         prefButtonLabelStringID = "spaceAlert.over5GB.prefButtonWin.label";
         prefButtonAccesskeyStringID = "spaceAlert.over5GB.prefButtonWin.accesskey";
       }
-      msg = prefStrBundle.getString(descriptionStringID);
+      msg = prefStrBundle.getFormattedString(descriptionStringID, [brandShortName]);
       buttons.push({
         label: prefStrBundle.getString(prefButtonLabelStringID),
         accessKey: prefStrBundle.getString(prefButtonAccesskeyStringID),
         callback(notificationBar, button) {
           gBrowser.ownerGlobal.openPreferences("advanced", { advancedTab: "networkTab" });
         }
       });
     }
@@ -3430,28 +3431,28 @@ var PrintPreviewListener = {
   _tabBeforePrintPreview: null,
   _simplifyPageTab: null,
 
   getPrintPreviewBrowser() {
     if (!this._printPreviewTab) {
       let browser = gBrowser.selectedBrowser;
       let preferredRemoteType = browser.remoteType;
       this._tabBeforePrintPreview = gBrowser.selectedTab;
-      this._printPreviewTab = gBrowser.loadOneTab("about:blank", {
+      this._printPreviewTab = gBrowser.loadOneTab("about:printpreview", {
         inBackground: false,
         preferredRemoteType,
         sameProcessAsFrameLoader: browser.frameLoader
       });
       gBrowser.selectedTab = this._printPreviewTab;
     }
     return gBrowser.getBrowserForTab(this._printPreviewTab);
   },
   createSimplifiedBrowser() {
     let browser = this._tabBeforePrintPreview.linkedBrowser;
-    this._simplifyPageTab = gBrowser.loadOneTab("about:blank", {
+    this._simplifyPageTab = gBrowser.loadOneTab("about:printpreview", {
       inBackground: true,
       sameProcessAsFrameLoader: browser.frameLoader
      });
     return this.getSimplifiedSourceBrowser();
   },
   getSourceBrowser() {
     return this._tabBeforePrintPreview ?
       this._tabBeforePrintPreview.linkedBrowser : gBrowser.selectedBrowser;

--- a/browser/base/content/test/general/browser_audioTabIcon.js
+++ b/browser/base/content/test/general/browser_audioTabIcon.js
@@ -12,29 +12,42 @@ function* wait_for_tab_playing_event(tab
       is(tab.hasAttribute("soundplaying"), expectPlaying, "The tab should " + (expectPlaying ? "" : "not ") + "be playing");
       is(tab.soundPlaying, expectPlaying, "The tab should " + (expectPlaying ? "" : "not ") + "be playing");
       return true;
     }
     return false;
   });
 }
 
+function* is_audio_playing(tab) {
+  let browser = tab.linkedBrowser;
+  let isPlaying = yield ContentTask.spawn(browser, {}, function* () {
+    let audio = content.document.querySelector("audio");
+    return !audio.paused;
+  });
+  return isPlaying;
+}
+
 function* play(tab) {
   let browser = tab.linkedBrowser;
   yield ContentTask.spawn(browser, {}, function* () {
     let audio = content.document.querySelector("audio");
     audio.play();
   });
 
+  // If the tab has already be muted, it means the tab won't get soundplaying,
+  // so we don't need to check this attribute.
+  if (browser.audioMuted) {
+      return;
+  }
+
   yield wait_for_tab_playing_event(tab, true);
 }
 
 function* pause(tab, options) {
-  ok(tab.hasAttribute("soundplaying"), "The tab should have the soundplaying attribute when pause() is called");
-
   let extendedDelay = options && options.extendedDelay;
   if (extendedDelay) {
     // Use 10s to remove possibility of race condition with attr removal.
     Services.prefs.setIntPref(TABATTR_REMOVAL_PREFNAME, 10000);
   }
 
   try {
     let browser = tab.linkedBrowser;
@@ -42,16 +55,22 @@ function* pause(tab, options) {
       BrowserTestUtils.waitForEvent(browser, "DOMAudioPlaybackStopped", "DOMAudioPlaybackStopped event should get fired after pause");
     let awaitTabPausedAttrModified =
       wait_for_tab_playing_event(tab, false);
     yield ContentTask.spawn(browser, {}, function* () {
       let audio = content.document.querySelector("audio");
       audio.pause();
     });
 
+    // If the tab has already be muted, it means the tab won't have soundplaying,
+    // so we don't need to check this attribute.
+    if (browser.audioMuted) {
+      return;
+    }
+
     if (extendedDelay) {
       ok(tab.hasAttribute("soundplaying"), "The tab should still have the soundplaying attribute immediately after pausing");
 
       yield awaitDOMAudioPlaybackStopped;
       ok(tab.hasAttribute("soundplaying"), "The tab should still have the soundplaying attribute immediately after DOMAudioPlaybackStopped");
     }
 
     yield awaitTabPausedAttrModified;
@@ -136,16 +155,23 @@ function* test_mute_tab(tab, icon, expec
   let tooltip = document.getElementById("tabbrowser-tab-tooltip");
 
   yield hover_icon(icon, tooltip);
   EventUtils.synthesizeMouseAtCenter(icon, {button: 0});
   leave_icon(icon);
 
   is(gBrowser.selectedTab, activeTab, "Clicking on mute should not change the currently selected tab");
 
+  // If the audio is playing, we should check whether clicking on icon affects
+  // the media element's playing state.
+  let isAudioPlaying = yield is_audio_playing(tab);
+  if (isAudioPlaying) {
+    yield wait_for_tab_playing_event(tab, !expectMuted);
+  }
+
   return mutedPromise;
 }
 
 function get_tab_state(tab) {
   const ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
   return JSON.parse(ss.getTabState(tab));
 }
 
@@ -164,17 +190,17 @@ function* test_muting_using_menu(tab, ex
   is(toggleMute.accessKey, expectedAccessKey, "Correct accessKey expected");
 
   is(toggleMute.hasAttribute("muted"), expectMuted, "Should have the correct state for the muted attribute");
   ok(!toggleMute.hasAttribute("soundplaying"), "Should not have the soundplaying attribute");
 
   yield play(tab);
 
   is(toggleMute.hasAttribute("muted"), expectMuted, "Should have the correct state for the muted attribute");
-  ok(toggleMute.hasAttribute("soundplaying"), "Should have the soundplaying attribute");
+  is(!toggleMute.hasAttribute("soundplaying"), expectMuted, "The value of soundplaying attribute is incorrect");
 
   yield pause(tab);
 
   is(toggleMute.hasAttribute("muted"), expectMuted, "Should have the correct state for the muted attribute");
   ok(!toggleMute.hasAttribute("soundplaying"), "Should not have the soundplaying attribute");
 
   // Click on the menu and wait for the tab to be muted.
   let mutedPromise = get_wait_for_mute_promise(tab, !expectMuted);
@@ -229,32 +255,32 @@ function* test_playing_icon_on_tab(tab, 
   // Make sure it's possible to mute using the context menu.
   yield test_muting_using_menu(tab, false);
 
   // Make sure it's possible to unmute using the context menu.
   yield test_muting_using_menu(tab, true);
 }
 
 function* test_swapped_browser_while_playing(oldTab, newBrowser) {
+  // The tab was muted so it won't have soundplaying attribute even it's playing.
   ok(oldTab.hasAttribute("muted"), "Expected the correct muted attribute on the old tab");
   is(oldTab.muteReason, null, "Expected the correct muteReason attribute on the old tab");
-  ok(oldTab.hasAttribute("soundplaying"), "Expected the correct soundplaying attribute on the old tab");
+  ok(!oldTab.hasAttribute("soundplaying"), "Expected the correct soundplaying attribute on the old tab");
 
   let newTab = gBrowser.getTabForBrowser(newBrowser);
   let AttrChangePromise = BrowserTestUtils.waitForEvent(newTab, "TabAttrModified", false, event => {
-    return event.detail.changed.includes("soundplaying") &&
-           event.detail.changed.includes("muted");
+    return event.detail.changed.includes("muted");
   });
 
   gBrowser.swapBrowsersAndCloseOther(newTab, oldTab);
   yield AttrChangePromise;
 
   ok(newTab.hasAttribute("muted"), "Expected the correct muted attribute on the new tab");
   is(newTab.muteReason, null, "Expected the correct muteReason property on the new tab");
-  ok(newTab.hasAttribute("soundplaying"), "Expected the correct soundplaying attribute on the new tab");
+  ok(!newTab.hasAttribute("soundplaying"), "Expected the correct soundplaying attribute on the new tab");
 
   let icon = document.getAnonymousElementByAttribute(newTab, "anonid",
                                                      "soundplaying-icon");
   yield test_tooltip(icon, "Unmute tab", true);
 }
 
 function* test_swapped_browser_while_not_playing(oldTab, newBrowser) {
   ok(oldTab.hasAttribute("muted"), "Expected the correct muted attribute on the old tab");

--- a/browser/base/content/test/referrer/head.js
+++ b/browser/base/content/test/referrer/head.js
@@ -137,17 +137,17 @@ function delayedStartupFinished(aWindow)
  * Waits for some (any) tab to load. The caller triggers the load.
  * @param aWindow The window where to wait for a tab to load.
  * @return {Promise}
  * @resolves With the tab once it's loaded.
  */
 function someTabLoaded(aWindow) {
   return new Promise(function(resolve) {
     aWindow.gBrowser.addEventListener("load", function onLoad(aEvent) {
-      if (aWindow.location === "about:blank") {
+      if (aWindow.location.href === "about:blank") {
         return;
       }
       let tab = aWindow.gBrowser._getTabForContentWindow(
           aEvent.target.defaultView.top);
       if (tab) {
         aWindow.gBrowser.removeEventListener("load", onLoad, true);
         resolve(tab);
       }

--- a/browser/components/customizableui/CustomizableWidgets.jsm
+++ b/browser/components/customizableui/CustomizableWidgets.jsm
@@ -304,16 +304,18 @@ const CustomizableWidgets = [
     viewId: "PanelUI-remotetabs",
     defaultArea: CustomizableUI.AREA_PANEL,
     deckIndices: {
       DECKINDEX_TABS: 0,
       DECKINDEX_TABSDISABLED: 1,
       DECKINDEX_FETCHING: 2,
       DECKINDEX_NOCLIENTS: 3,
     },
+    TABS_PER_PAGE: 25,
+    NEXT_PAGE_MIN_TABS: 5, // Minimum number of tabs displayed when we click "Show All"
     onCreated(aNode) {
       // Add an observer to the button so we get the animation during sync.
       // (Note the observer sets many attributes, including label and
       // tooltiptext, but we only want the 'syncstatus' attribute for the
       // animation)
       let doc = aNode.ownerDocument;
       let obnode = doc.createElementNS(kNSXUL, "observes");
       obnode.setAttribute("element", "sync-status");
@@ -396,23 +398,23 @@ const CustomizableWidgets = [
       // We call setAttribute instead of relying on the XBL property setter due
       // to things going wrong when we try and set the index before the XBL
       // binding has been created - see bug 1241851 for the gory details.
       deck.setAttribute("selectedIndex", index);
     },
 
     _showTabsPromise: Promise.resolve(),
     // Update the tab list after any existing in-flight updates are complete.
-    _showTabs() {
+    _showTabs(paginationInfo) {
       this._showTabsPromise = this._showTabsPromise.then(() => {
-        return this.__showTabs();
+        return this.__showTabs(paginationInfo);
       });
     },
     // Return a new promise to update the tab list.
-    __showTabs() {
+    __showTabs(paginationInfo) {
       let doc = this._tabsList.ownerDocument;
       return SyncedTabs.getTabClients().then(clients => {
         // The view may have been hidden while the promise was resolving.
         if (!this._tabsList) {
           return;
         }
         if (clients.length === 0 && !SyncedTabs.hasSyncedThisSession) {
           // the "fetching tabs" deck is being shown - let's leave it there.
@@ -422,26 +424,30 @@ const CustomizableWidgets = [
 
         if (clients.length === 0) {
           this.setDeckIndex(this.deckIndices.DECKINDEX_NOCLIENTS);
           return;
         }
 
         this.setDeckIndex(this.deckIndices.DECKINDEX_TABS);
         this._clearTabList();
-        SyncedTabs.sortTabClientsByLastUsed(clients, 50 /* maxTabs */);
+        SyncedTabs.sortTabClientsByLastUsed(clients);
         let fragment = doc.createDocumentFragment();
 
         for (let client of clients) {
           // add a menu separator for all clients other than the first.
           if (fragment.lastChild) {
             let separator = doc.createElementNS(kNSXUL, "menuseparator");
             fragment.appendChild(separator);
           }
-          this._appendClient(client, fragment);
+          if (paginationInfo && paginationInfo.clientId == client.id) {
+            this._appendClient(client, fragment, paginationInfo.maxTabs);
+          } else {
+            this._appendClient(client, fragment);
+          }
         }
         this._tabsList.appendChild(fragment);
       }).catch(err => {
         Cu.reportError(err);
       }).then(() => {
         // an observer for tests.
         Services.obs.notifyObservers(null, "synced-tabs-menu:test:tabs-updated", null);
       });
@@ -461,36 +467,56 @@ const CustomizableWidgets = [
       }
       let message = this._tabsList.getAttribute(messageAttr);
       let doc = this._tabsList.ownerDocument;
       let messageLabel = doc.createElementNS(kNSXUL, "label");
       messageLabel.textContent = message;
       appendTo.appendChild(messageLabel);
       return messageLabel;
     },
-    _appendClient(client, attachFragment) {
+    _appendClient(client, attachFragment, maxTabs = this.TABS_PER_PAGE) {
       let doc = attachFragment.ownerDocument;
       // Create the element for the remote client.
       let clientItem = doc.createElementNS(kNSXUL, "label");
       clientItem.setAttribute("itemtype", "client");
       let window = doc.defaultView;
       clientItem.setAttribute("tooltiptext",
         window.gSyncUI.formatLastSyncDate(new Date(client.lastModified)));
       clientItem.textContent = client.name;
 
       attachFragment.appendChild(clientItem);
 
       if (client.tabs.length == 0) {
         let label = this._appendMessageLabel("notabsforclientlabel", attachFragment);
         label.setAttribute("class", "PanelUI-remotetabs-notabsforclient-label");
       } else {
+        // If this page will display all tabs, show no additional buttons.
+        // If the next page will display all the remaining tabs, show a "Show All" button
+        // Otherwise, show a "Shore More" button
+        let hasNextPage = client.tabs.length > maxTabs;
+        let nextPageIsLastPage = hasNextPage && maxTabs + this.TABS_PER_PAGE >= client.tabs.length;
+        if (nextPageIsLastPage) {
+          // When the user clicks "Show All", try to have at least NEXT_PAGE_MIN_TABS more tabs
+          // to display in order to avoid user frustration
+          maxTabs = Math.min(client.tabs.length - this.NEXT_PAGE_MIN_TABS, maxTabs);
+        }
+        if (hasNextPage) {
+          client.tabs = client.tabs.slice(0, maxTabs);
+        }
         for (let tab of client.tabs) {
           let tabEnt = this._createTabElement(doc, tab);
           attachFragment.appendChild(tabEnt);
         }
+        if (hasNextPage) {
+          let showAllEnt = this._createShowMoreElement(doc, client.id,
+                                                       nextPageIsLastPage ?
+                                                       Infinity :
+                                                       maxTabs + this.TABS_PER_PAGE);
+          attachFragment.appendChild(showAllEnt);
+        }
       }
     },
     _createTabElement(doc, tabInfo) {
       let item = doc.createElementNS(kNSXUL, "toolbarbutton");
       let tooltipText = (tabInfo.title ? tabInfo.title + "\n" : "") + tabInfo.url;
       item.setAttribute("itemtype", "tab");
       item.setAttribute("class", "subviewbutton");
       item.setAttribute("targetURI", tabInfo.url);
@@ -501,16 +527,39 @@ const CustomizableWidgets = [
       // respects different buttons (eg, to open in a new tab).
       item.addEventListener("click", e => {
         doc.defaultView.openUILink(tabInfo.url, e);
         CustomizableUI.hidePanelForNode(item);
         BrowserUITelemetry.countSyncedTabEvent("open", "toolbarbutton-subview");
       });
       return item;
     },
+    _createShowMoreElement(doc, clientId, showCount) {
+      let labelAttr, tooltipAttr;
+      if (showCount === Infinity) {
+        labelAttr = "showAllLabel";
+        tooltipAttr = "showAllTooltipText";
+      } else {
+        labelAttr = "showMoreLabel";
+        tooltipAttr = "showMoreTooltipText";
+      }
+      let showAllItem = doc.createElementNS(kNSXUL, "toolbarbutton");
+      showAllItem.setAttribute("itemtype", "showmorebutton");
+      showAllItem.setAttribute("class", "subviewbutton");
+      let label = this._tabsList.getAttribute(labelAttr);
+      showAllItem.setAttribute("label", label);
+      let tooltipText = this._tabsList.getAttribute(tooltipAttr);
+      showAllItem.setAttribute("tooltiptext", tooltipText);
+      showAllItem.addEventListener("click", e => {
+        e.preventDefault();
+        e.stopPropagation();
+        this._showTabs({ clientId, maxTabs: showCount });
+      });
+      return showAllItem;
+    }
   }, {
     id: "privatebrowsing-button",
     shortcutId: "key_privatebrowsing",
     defaultArea: CustomizableUI.AREA_PANEL,
     onCommand(e) {
       let win = e.target.ownerGlobal;
       win.OpenBrowserWindow({private: true});
     }

--- a/browser/components/customizableui/content/panelUI.inc.xul
+++ b/browser/components/customizableui/content/panelUI.inc.xul
@@ -120,16 +120,20 @@
                            oncommand="gSyncUI.doSync();"
                            closemenu="none"/>
             <menuseparator id="PanelUI-remotetabs-separator"/>
           </vbox>
           <deck id="PanelUI-remotetabs-deck">
             <!-- Sync is ready to Sync and the "tabs" engine is enabled -->
             <vbox id="PanelUI-remotetabs-tabspane">
               <vbox id="PanelUI-remotetabs-tabslist"
+                    showAllLabel="&appMenuRemoteTabs.showAll.label;"
+                    showAllTooltipText="&appMenuRemoteTabs.showAll.tooltip;"
+                    showMoreLabel="&appMenuRemoteTabs.showMore.label;"
+                    showMoreTooltipText="&appMenuRemoteTabs.showMore.tooltip;"
                     notabsforclientlabel="&appMenuRemoteTabs.notabs.label;"
                     />
             </vbox>
             <!-- Sync is ready to Sync but the "tabs" engine isn't enabled-->
             <hbox id="PanelUI-remotetabs-tabsdisabledpane" pack="center" flex="1">
               <vbox class="PanelUI-remotetabs-instruction-box">
                 <hbox pack="center">
                   <html:img class="fxaSyncIllustration" src="chrome://browser/skin/fxa/sync-illustration.svg"/>

--- a/browser/components/customizableui/test/browser.ini
+++ b/browser/components/customizableui/test/browser.ini
@@ -95,17 +95,16 @@ skip-if = os == "linux" # Intermittent f
 [browser_948985_non_removable_defaultArea.js]
 [browser_952963_areaType_getter_no_area.js]
 [browser_956602_remove_special_widget.js]
 [browser_962069_drag_to_overflow_chevron.js]
 [browser_962884_opt_in_disable_hyphens.js]
 [browser_963639_customizing_attribute_non_customizable_toolbar.js]
 [browser_967000_button_charEncoding.js]
 [browser_967000_button_feeds.js]
-[browser_967000_button_sync.js]
 [browser_968447_bookmarks_toolbar_items_in_panel.js]
 skip-if = os == "linux" # Intemittent failures - bug 979207
 [browser_968565_insert_before_hidden_items.js]
 [browser_969427_recreate_destroyed_widget_after_reset.js]
 [browser_969661_character_encoding_navbar_disabled.js]
 [browser_970511_undo_restore_default.js]
 [browser_972267_customizationchange_events.js]
 [browser_973641_button_addon.js]
@@ -146,9 +145,10 @@ skip-if = os == "mac"
 [browser_1087303_button_preferences.js]
 [browser_1089591_still_customizable_after_reset.js]
 [browser_1096763_seen_widgets_post_reset.js]
 [browser_1161838_inserted_new_default_buttons.js]
 [browser_bootstrapped_custom_toolbar.js]
 [browser_customizemode_contextmenu_menubuttonstate.js]
 [browser_panel_toggle.js]
 [browser_switch_to_customize_mode.js]
+[browser_synced_tabs_menu.js]
 [browser_check_tooltips_in_navbar.js]

deleted file mode 100644
--- a/browser/components/customizableui/test/browser_967000_button_sync.js
+++ /dev/null
@@ -1,337 +0,0 @@
-/* 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/. */
-
-"use strict";
-
-requestLongerTimeout(2);
-
-let {SyncedTabs} = Cu.import("resource://services-sync/SyncedTabs.jsm", {});
-
-XPCOMUtils.defineLazyModuleGetter(this, "UITour", "resource:///modules/UITour.jsm");
-
-// These are available on the widget implementation, but it seems impossible
-// to grab that impl at runtime.
-const DECKINDEX_TABS = 0;
-const DECKINDEX_TABSDISABLED = 1;
-const DECKINDEX_FETCHING = 2;
-const DECKINDEX_NOCLIENTS = 3;
-
-var initialLocation = gBrowser.currentURI.spec;
-var newTab = null;
-
-// A helper to notify there are new tabs. Returns a promise that is resolved
-// once the UI has been updated.
-function updateTabsPanel() {
-  let promiseTabsUpdated = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
-  Services.obs.notifyObservers(null, SyncedTabs.TOPIC_TABS_CHANGED, null);
-  return promiseTabsUpdated;
-}
-
-// This is the mock we use for SyncedTabs.jsm - tests may override various
-// functions.
-let mockedInternal = {
-  get isConfiguredToSyncTabs() { return true; },
-  getTabClients() { return []; },
-  syncTabs() {},
-  hasSyncedThisSession: false,
-};
-
-
-add_task(function* setup() {
-  let oldInternal = SyncedTabs._internal;
-  SyncedTabs._internal = mockedInternal;
-
-  // This test hacks some observer states to simulate a user being signed
-  // in to Sync - restore them when the test completes.
-  let initialObserverStates = {};
-  for (let id of ["sync-reauth-state", "sync-setup-state", "sync-syncnow-state"]) {
-    initialObserverStates[id] = document.getElementById(id).hidden;
-  }
-
-  registerCleanupFunction(() => {
-    SyncedTabs._internal = oldInternal;
-    for (let [id, initial] of Object.entries(initialObserverStates)) {
-      document.getElementById(id).hidden = initial;
-    }
-  });
-});
-
-// The test expects the about:preferences#sync page to open in the current tab
-function* openPrefsFromMenuPanel(expectedPanelId, entryPoint) {
-  info("Check Sync button functionality");
-  Services.prefs.setCharPref("identity.fxaccounts.remote.signup.uri", "http://example.com/");
-
-  // check the button's functionality
-  yield PanelUI.show();
-
-  if (entryPoint == "uitour") {
-    UITour.tourBrowsersByWindow.set(window, new Set());
-    UITour.tourBrowsersByWindow.get(window).add(gBrowser.selectedBrowser);
-  }
-
-  let syncButton = document.getElementById("sync-button");
-  ok(syncButton, "The Sync button was added to the Panel Menu");
-
-  syncButton.click();
-  let syncPanel = document.getElementById("PanelUI-remotetabs");
-  ok(syncPanel.getAttribute("current"), "Sync Panel is in view");
-
-  // Sync is not configured - verify that state is reflected.
-  let subpanel = document.getElementById(expectedPanelId)
-  ok(!subpanel.hidden, "sync setup element is visible");
-
-  // Find and click the "setup" button.
-  let setupButton = subpanel.querySelector(".PanelUI-remotetabs-prefs-button");
-  setupButton.click();
-
-  let deferred = Promise.defer();
-  let handler = (e) => {
-    if (e.originalTarget != gBrowser.selectedBrowser.contentDocument ||
-        e.target.location.href == "about:blank") {
-      info("Skipping spurious 'load' event for " + e.target.location.href);
-      return;
-    }
-    gBrowser.selectedBrowser.removeEventListener("load", handler, true);
-    deferred.resolve();
-  }
-  gBrowser.selectedBrowser.addEventListener("load", handler, true);
-
-  yield deferred.promise;
-  newTab = gBrowser.selectedTab;
-
-  is(gBrowser.currentURI.spec, "about:preferences?entrypoint=" + entryPoint + "#sync",
-    "Firefox Sync preference page opened with `menupanel` entrypoint");
-  ok(!isPanelUIOpen(), "The panel closed");
-
-  if (isPanelUIOpen()) {
-    let panelHidePromise = promisePanelHidden(window);
-    PanelUI.hide();
-    yield panelHidePromise;
-  }
-}
-
-function* asyncCleanup() {
-  Services.prefs.clearUserPref("identity.fxaccounts.remote.signup.uri");
-  // reset the panel UI to the default state
-  yield resetCustomization();
-  ok(CustomizableUI.inDefaultState, "The panel UI is in default state again.");
-
-  // restore the tabs
-  gBrowser.addTab(initialLocation);
-  gBrowser.removeTab(newTab);
-  UITour.tourBrowsersByWindow.delete(window);
-}
-
-// When Sync is not setup.
-add_task(() => openPrefsFromMenuPanel("PanelUI-remotetabs-setupsync", "synced-tabs"));
-add_task(asyncCleanup);
-
-// When Sync is configured in a "needs reauthentication" state.
-add_task(function* () {
-  // configure our broadcasters so we are in the right state.
-  document.getElementById("sync-reauth-state").hidden = false;
-  document.getElementById("sync-setup-state").hidden = true;
-  document.getElementById("sync-syncnow-state").hidden = true;
-  yield openPrefsFromMenuPanel("PanelUI-remotetabs-reauthsync", "synced-tabs")
-});
-
-// Test the mobile promo links
-add_task(function* () {
-  // change the preferences for the mobile links.
-  Services.prefs.setCharPref("identity.mobilepromo.android", "http://example.com/?os=android&tail=");
-  Services.prefs.setCharPref("identity.mobilepromo.ios", "http://example.com/?os=ios&tail=");
-
-  mockedInternal.getTabClients = () => [];
-  mockedInternal.syncTabs = () => Promise.resolve();
-
-  document.getElementById("sync-reauth-state").hidden = true;
-  document.getElementById("sync-setup-state").hidden = true;
-  document.getElementById("sync-syncnow-state").hidden = false;
-
-  let syncPanel = document.getElementById("PanelUI-remotetabs");
-  let links = syncPanel.querySelectorAll(".remotetabs-promo-link");
-
-  is(links.length, 2, "found 2 links as expected");
-
-  // test each link and left and middle mouse buttons
-  for (let link of links) {
-    for (let button = 0; button < 2; button++) {
-      yield PanelUI.show();
-      EventUtils.sendMouseEvent({ type: "click", button }, link, window);
-      // the panel should have been closed.
-      ok(!isPanelUIOpen(), "click closed the panel");
-      // should be a new tab - wait for the load.
-      is(gBrowser.tabs.length, 2, "there's a new tab");
-      yield new Promise(resolve => {
-        if (gBrowser.selectedBrowser.currentURI.spec == "about:blank") {
-          gBrowser.selectedBrowser.addEventListener("load", function(e) {
-            resolve();
-          }, {capture: true, once: true});
-          return;
-        }
-        // the new tab has already transitioned away from about:blank so we
-        // are good to go.
-        resolve();
-      });
-
-      let os = link.getAttribute("mobile-promo-os");
-      let expectedUrl = `http://example.com/?os=${os}&tail=synced-tabs`;
-      is(gBrowser.selectedBrowser.currentURI.spec, expectedUrl, "correct URL");
-      gBrowser.removeTab(gBrowser.selectedTab);
-    }
-  }
-
-  // test each link and right mouse button - should be a noop.
-  yield PanelUI.show();
-  for (let link of links) {
-    EventUtils.sendMouseEvent({ type: "click", button: 2 }, link, window);
-    // the panel should still be open
-    ok(isPanelUIOpen(), "panel remains open after right-click");
-    is(gBrowser.tabs.length, 1, "no new tab was opened");
-  }
-  PanelUI.hide();
-
-  Services.prefs.clearUserPref("identity.mobilepromo.android");
-  Services.prefs.clearUserPref("identity.mobilepromo.ios");
-});
-
-// Test the "Sync Now" button
-add_task(function* () {
-  mockedInternal.getTabClients = () => [];
-  mockedInternal.syncTabs = () => {
-    return Promise.resolve();
-  }
-
-  // configure our broadcasters so we are in the right state.
-  document.getElementById("sync-reauth-state").hidden = true;
-  document.getElementById("sync-setup-state").hidden = true;
-  document.getElementById("sync-syncnow-state").hidden = false;
-
-  yield PanelUI.show();
-  document.getElementById("sync-button").click();
-  let syncPanel = document.getElementById("PanelUI-remotetabs");
-  ok(syncPanel.getAttribute("current"), "Sync Panel is in view");
-
-  let subpanel = document.getElementById("PanelUI-remotetabs-main")
-  ok(!subpanel.hidden, "main pane is visible");
-  let deck = document.getElementById("PanelUI-remotetabs-deck");
-
-  // The widget is still fetching tabs, as we've neutered everything that
-  // provides them
-  is(deck.selectedIndex, DECKINDEX_FETCHING, "first deck entry is visible");
-
-  let syncNowButton = document.getElementById("PanelUI-remotetabs-syncnow");
-
-  let didSync = false;
-  let oldDoSync = gSyncUI.doSync;
-  gSyncUI.doSync = function() {
-    didSync = true;
-    mockedInternal.hasSyncedThisSession = true;
-    gSyncUI.doSync = oldDoSync;
-  }
-  syncNowButton.click();
-  ok(didSync, "clicking the button called the correct function");
-
-  // Tell the widget there are tabs available, but with zero clients.
-  mockedInternal.getTabClients = () => {
-    return Promise.resolve([]);
-  }
-  yield updateTabsPanel();
-  // The UI should be showing the "no clients" pane.
-  is(deck.selectedIndex, DECKINDEX_NOCLIENTS, "no-clients deck entry is visible");
-
-  // Tell the widget there are tabs available - we have 3 clients, one with no
-  // tabs.
-  mockedInternal.getTabClients = () => {
-    return Promise.resolve([
-      {
-        id: "guid_mobile",
-        type: "client",
-        name: "My Phone",
-        tabs: [],
-      },
-      {
-        id: "guid_desktop",
-        type: "client",
-        name: "My Desktop",
-        tabs: [
-          {
-            title: "http://example.com/10",
-            lastUsed: 10, // the most recent
-          },
-          {
-            title: "http://example.com/1",
-            lastUsed: 1, // the least recent.
-          },
-          {
-            title: "http://example.com/5",
-            lastUsed: 5,
-          },
-        ],
-      },
-      {
-        id: "guid_second_desktop",
-        name: "My Other Desktop",
-        tabs: [
-          {
-            title: "http://example.com/6",
-            lastUsed: 6,
-          }
-        ],
-      },
-    ]);
-  };
-  yield updateTabsPanel();
-
-  // The UI should be showing tabs!
-  is(deck.selectedIndex, DECKINDEX_TABS, "no-clients deck entry is visible");
-  let tabList = document.getElementById("PanelUI-remotetabs-tabslist");
-  let node = tabList.firstChild;
-  // First entry should be the client with the most-recent tab.
-  is(node.getAttribute("itemtype"), "client", "node is a client entry");
-  is(node.textContent, "My Desktop", "correct client");
-  // Next entry is the most-recent tab
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "tab", "node is a tab");
-  is(node.getAttribute("label"), "http://example.com/10");
-
-  // Next entry is the next-most-recent tab
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "tab", "node is a tab");
-  is(node.getAttribute("label"), "http://example.com/5");
-
-  // Next entry is the least-recent tab from the first client.
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "tab", "node is a tab");
-  is(node.getAttribute("label"), "http://example.com/1");
-
-  // Next is a menuseparator between the clients.
-  node = node.nextSibling;
-  is(node.nodeName, "menuseparator");
-
-  // Next is the client with 1 tab.
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "client", "node is a client entry");
-  is(node.textContent, "My Other Desktop", "correct client");
-  // Its single tab
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "tab", "node is a tab");
-  is(node.getAttribute("label"), "http://example.com/6");
-
-  // Next is a menuseparator between the clients.
-  node = node.nextSibling;
-  is(node.nodeName, "menuseparator");
-
-  // Next is the client with no tab.
-  node = node.nextSibling;
-  is(node.getAttribute("itemtype"), "client", "node is a client entry");
-  is(node.textContent, "My Phone", "correct client");
-  // There is a single node saying there's no tabs for the client.
-  node = node.nextSibling;
-  is(node.nodeName, "label", "node is a label");
-  is(node.getAttribute("itemtype"), "", "node is neither a tab nor a client");
-
-  node = node.nextSibling;
-  is(node, null, "no more entries");
-});

new file mode 100644
--- /dev/null
+++ b/browser/components/customizableui/test/browser_synced_tabs_menu.js
@@ -0,0 +1,427 @@
+/* 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/. */
+
+"use strict";
+
+requestLongerTimeout(2);
+
+let {SyncedTabs} = Cu.import("resource://services-sync/SyncedTabs.jsm", {});
+
+XPCOMUtils.defineLazyModuleGetter(this, "UITour", "resource:///modules/UITour.jsm");
+
+// These are available on the widget implementation, but it seems impossible
+// to grab that impl at runtime.
+const DECKINDEX_TABS = 0;
+const DECKINDEX_TABSDISABLED = 1;
+const DECKINDEX_FETCHING = 2;
+const DECKINDEX_NOCLIENTS = 3;
+
+var initialLocation = gBrowser.currentURI.spec;
+var newTab = null;
+
+// A helper to notify there are new tabs. Returns a promise that is resolved
+// once the UI has been updated.
+function updateTabsPanel() {
+  let promiseTabsUpdated = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
+  Services.obs.notifyObservers(null, SyncedTabs.TOPIC_TABS_CHANGED, null);
+  return promiseTabsUpdated;
+}
+
+// This is the mock we use for SyncedTabs.jsm - tests may override various
+// functions.
+let mockedInternal = {
+  get isConfiguredToSyncTabs() { return true; },
+  getTabClients() { return Promise.resolve([]); },
+  syncTabs() { return Promise.resolve(); },
+  hasSyncedThisSession: false,
+};
+
+
+add_task(function* setup() {
+  let oldInternal = SyncedTabs._internal;
+  SyncedTabs._internal = mockedInternal;
+
+  // This test hacks some observer states to simulate a user being signed
+  // in to Sync - restore them when the test completes.
+  let initialObserverStates = {};
+  for (let id of ["sync-reauth-state", "sync-setup-state", "sync-syncnow-state"]) {
+    initialObserverStates[id] = document.getElementById(id).hidden;
+  }
+
+  registerCleanupFunction(() => {
+    SyncedTabs._internal = oldInternal;
+    for (let [id, initial] of Object.entries(initialObserverStates)) {
+      document.getElementById(id).hidden = initial;
+    }
+  });
+});
+
+// The test expects the about:preferences#sync page to open in the current tab
+function* openPrefsFromMenuPanel(expectedPanelId, entryPoint) {
+  info("Check Sync button functionality");
+  Services.prefs.setCharPref("identity.fxaccounts.remote.signup.uri", "http://example.com/");
+
+  // check the button's functionality
+  yield PanelUI.show();
+
+  if (entryPoint == "uitour") {
+    UITour.tourBrowsersByWindow.set(window, new Set());
+    UITour.tourBrowsersByWindow.get(window).add(gBrowser.selectedBrowser);
+  }
+
+  let syncButton = document.getElementById("sync-button");
+  ok(syncButton, "The Sync button was added to the Panel Menu");
+
+  let tabsUpdatedPromise = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
+  syncButton.click();
+  yield tabsUpdatedPromise;
+  let syncPanel = document.getElementById("PanelUI-remotetabs");
+  ok(syncPanel.getAttribute("current"), "Sync Panel is in view");
+
+  // Sync is not configured - verify that state is reflected.
+  let subpanel = document.getElementById(expectedPanelId)
+  ok(!subpanel.hidden, "sync setup element is visible");
+
+  // Find and click the "setup" button.
+  let setupButton = subpanel.querySelector(".PanelUI-remotetabs-prefs-button");
+  setupButton.click();
+
+  let deferred = Promise.defer();
+  let handler = (e) => {
+    if (e.originalTarget != gBrowser.selectedBrowser.contentDocument ||
+        e.target.location.href == "about:blank") {
+      info("Skipping spurious 'load' event for " + e.target.location.href);
+      return;
+    }
+    gBrowser.selectedBrowser.removeEventListener("load", handler, true);
+    deferred.resolve();
+  }
+  gBrowser.selectedBrowser.addEventListener("load", handler, true);
+
+  yield deferred.promise;
+  newTab = gBrowser.selectedTab;
+
+  is(gBrowser.currentURI.spec, "about:preferences?entrypoint=" + entryPoint + "#sync",
+    "Firefox Sync preference page opened with `menupanel` entrypoint");
+  ok(!isPanelUIOpen(), "The panel closed");
+
+  if (isPanelUIOpen()) {
+    yield panelUIHide();
+  }
+}
+
+function panelUIHide() {
+  let panelHidePromise = promisePanelHidden(window);
+  PanelUI.hide();
+  return panelHidePromise;
+}
+
+function* asyncCleanup() {
+  Services.prefs.clearUserPref("identity.fxaccounts.remote.signup.uri");
+  // reset the panel UI to the default state
+  yield resetCustomization();
+  ok(CustomizableUI.inDefaultState, "The panel UI is in default state again.");
+
+  // restore the tabs
+  gBrowser.addTab(initialLocation);
+  gBrowser.removeTab(newTab);
+  UITour.tourBrowsersByWindow.delete(window);
+}
+
+// When Sync is not setup.
+add_task(function* () {
+  document.getElementById("sync-reauth-state").hidden = true;
+  document.getElementById("sync-setup-state").hidden = false;
+  document.getElementById("sync-syncnow-state").hidden = true;
+  yield openPrefsFromMenuPanel("PanelUI-remotetabs-setupsync", "synced-tabs")
+});
+add_task(asyncCleanup);
+
+// When Sync is configured in a "needs reauthentication" state.
+add_task(function* () {
+  // configure our broadcasters so we are in the right state.
+  document.getElementById("sync-reauth-state").hidden = false;
+  document.getElementById("sync-setup-state").hidden = true;
+  document.getElementById("sync-syncnow-state").hidden = true;
+  yield openPrefsFromMenuPanel("PanelUI-remotetabs-reauthsync", "synced-tabs")
+});
+
+// Test the mobile promo links
+add_task(function* () {
+  // change the preferences for the mobile links.
+  Services.prefs.setCharPref("identity.mobilepromo.android", "http://example.com/?os=android&tail=");
+  Services.prefs.setCharPref("identity.mobilepromo.ios", "http://example.com/?os=ios&tail=");
+
+  document.getElementById("sync-reauth-state").hidden = true;
+  document.getElementById("sync-setup-state").hidden = true;
+  document.getElementById("sync-syncnow-state").hidden = false;
+
+  let syncPanel = document.getElementById("PanelUI-remotetabs");
+  let links = syncPanel.querySelectorAll(".remotetabs-promo-link");
+
+  is(links.length, 2, "found 2 links as expected");
+
+  // test each link and left and middle mouse buttons
+  for (let link of links) {
+    for (let button = 0; button < 2; button++) {
+      yield PanelUI.show();
+      EventUtils.sendMouseEvent({ type: "click", button }, link, window);
+      // the panel should have been closed.
+      ok(!isPanelUIOpen(), "click closed the panel");
+      // should be a new tab - wait for the load.
+      is(gBrowser.tabs.length, 2, "there's a new tab");
+      yield new Promise(resolve => {
+        if (gBrowser.selectedBrowser.currentURI.spec == "about:blank") {
+          gBrowser.selectedBrowser.addEventListener("load", function(e) {
+            resolve();
+          }, {capture: true, once: true});
+          return;
+        }
+        // the new tab has already transitioned away from about:blank so we
+        // are good to go.
+        resolve();
+      });
+
+      let os = link.getAttribute("mobile-promo-os");
+      let expectedUrl = `http://example.com/?os=${os}&tail=synced-tabs`;
+      is(gBrowser.selectedBrowser.currentURI.spec, expectedUrl, "correct URL");
+      gBrowser.removeTab(gBrowser.selectedTab);
+    }
+  }
+
+  // test each link and right mouse button - should be a noop.
+  yield PanelUI.show();
+  for (let link of links) {
+    EventUtils.sendMouseEvent({ type: "click", button: 2 }, link, window);
+    // the panel should still be open
+    ok(isPanelUIOpen(), "panel remains open after right-click");
+    is(gBrowser.tabs.length, 1, "no new tab was opened");
+  }
+  yield panelUIHide();
+
+  Services.prefs.clearUserPref("identity.mobilepromo.android");
+  Services.prefs.clearUserPref("identity.mobilepromo.ios");
+});
+
+// Test the "Sync Now" button
+add_task(function* () {
+  // configure our broadcasters so we are in the right state.
+  document.getElementById("sync-reauth-state").hidden = true;
+  document.getElementById("sync-setup-state").hidden = true;
+  document.getElementById("sync-syncnow-state").hidden = false;
+
+  yield PanelUI.show();
+  let tabsUpdatedPromise = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
+  document.getElementById("sync-button").click();
+  yield tabsUpdatedPromise;
+  let syncPanel = document.getElementById("PanelUI-remotetabs");
+  ok(syncPanel.getAttribute("current"), "Sync Panel is in view");
+
+  let subpanel = document.getElementById("PanelUI-remotetabs-main")
+  ok(!subpanel.hidden, "main pane is visible");
+  let deck = document.getElementById("PanelUI-remotetabs-deck");
+
+  // The widget is still fetching tabs, as we've neutered everything that
+  // provides them
+  is(deck.selectedIndex, DECKINDEX_FETCHING, "first deck entry is visible");
+
+  let syncNowButton = document.getElementById("PanelUI-remotetabs-syncnow");
+
+  let didSync = false;
+  let oldDoSync = gSyncUI.doSync;
+  gSyncUI.doSync = function() {
+    didSync = true;
+    mockedInternal.hasSyncedThisSession = true;
+    gSyncUI.doSync = oldDoSync;
+  }
+  syncNowButton.click();
+  ok(didSync, "clicking the button called the correct function");
+
+  // Tell the widget there are tabs available, but with zero clients.
+  mockedInternal.getTabClients = () => {
+    return Promise.resolve([]);
+  }
+  yield updateTabsPanel();
+  // The UI should be showing the "no clients" pane.
+  is(deck.selectedIndex, DECKINDEX_NOCLIENTS, "no-clients deck entry is visible");
+
+  // Tell the widget there are tabs available - we have 3 clients, one with no
+  // tabs.
+  mockedInternal.getTabClients = () => {
+    return Promise.resolve([
+      {
+        id: "guid_mobile",
+        type: "client",
+        name: "My Phone",
+        tabs: [],
+      },
+      {
+        id: "guid_desktop",
+        type: "client",
+        name: "My Desktop",
+        tabs: [
+          {
+            title: "http://example.com/10",
+            lastUsed: 10, // the most recent
+          },
+          {
+            title: "http://example.com/1",
+            lastUsed: 1, // the least recent.
+          },
+          {
+            title: "http://example.com/5",
+            lastUsed: 5,
+          },
+        ],
+      },
+      {
+        id: "guid_second_desktop",
+        name: "My Other Desktop",
+        tabs: [
+          {
+            title: "http://example.com/6",
+            lastUsed: 6,
+          }
+        ],
+      },
+    ]);
+  };
+  yield updateTabsPanel();
+
+  // The UI should be showing tabs!
+  is(deck.selectedIndex, DECKINDEX_TABS, "no-clients deck entry is visible");
+  let tabList = document.getElementById("PanelUI-remotetabs-tabslist");
+  let node = tabList.firstChild;
+  // First entry should be the client with the most-recent tab.
+  is(node.getAttribute("itemtype"), "client", "node is a client entry");
+  is(node.textContent, "My Desktop", "correct client");
+  // Next entry is the most-recent tab
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "tab", "node is a tab");
+  is(node.getAttribute("label"), "http://example.com/10");
+
+  // Next entry is the next-most-recent tab
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "tab", "node is a tab");
+  is(node.getAttribute("label"), "http://example.com/5");
+
+  // Next entry is the least-recent tab from the first client.
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "tab", "node is a tab");
+  is(node.getAttribute("label"), "http://example.com/1");
+
+  // Next is a menuseparator between the clients.
+  node = node.nextSibling;
+  is(node.nodeName, "menuseparator");
+
+  // Next is the client with 1 tab.
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "client", "node is a client entry");
+  is(node.textContent, "My Other Desktop", "correct client");
+  // Its single tab
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "tab", "node is a tab");
+  is(node.getAttribute("label"), "http://example.com/6");
+
+  // Next is a menuseparator between the clients.
+  node = node.nextSibling;
+  is(node.nodeName, "menuseparator");
+
+  // Next is the client with no tab.
+  node = node.nextSibling;
+  is(node.getAttribute("itemtype"), "client", "node is a client entry");
+  is(node.textContent, "My Phone", "correct client");
+  // There is a single node saying there's no tabs for the client.
+  node = node.nextSibling;
+  is(node.nodeName, "label", "node is a label");
+  is(node.getAttribute("itemtype"), "", "node is neither a tab nor a client");
+
+  node = node.nextSibling;
+  is(node, null, "no more entries");
+
+  yield panelUIHide();
+});
+
+// Test the pagination capabilities (Show More/All tabs)
+add_task(function* () {
+  mockedInternal.getTabClients = () => {
+    return Promise.resolve([
+      {
+        id: "guid_desktop",
+        type: "client",
+        name: "My Desktop",
+        tabs: function() {
+          let allTabsDesktop = [];
+          // We choose 77 tabs, because TABS_PER_PAGE is 25, which means
+          // on the second to last page we should have 22 items shown
+          // (because we have to show at least NEXT_PAGE_MIN_TABS=5 tabs on the last page)
+          for (let i = 1; i <= 77; i++) {
+            allTabsDesktop.push({ title: "Tab #" + i });
+          }
+          return allTabsDesktop;
+        }(),
+      }
+    ]);
+  };
+
+  // configure our broadcasters so we are in the right state.
+  document.getElementById("sync-reauth-state").hidden = true;
+  document.getElementById("sync-setup-state").hidden = true;
+  document.getElementById("sync-syncnow-state").hidden = false;
+
+  yield PanelUI.show();
+  let tabsUpdatedPromise = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
+  document.getElementById("sync-button").click();
+  yield tabsUpdatedPromise;
+
+  // Check pre-conditions
+  let syncPanel = document.getElementById("PanelUI-remotetabs");
+  ok(syncPanel.getAttribute("current"), "Sync Panel is in view");
+  let subpanel = document.getElementById("PanelUI-remotetabs-main")
+  ok(!subpanel.hidden, "main pane is visible");
+  let deck = document.getElementById("PanelUI-remotetabs-deck");
+  is(deck.selectedIndex, DECKINDEX_TABS, "we should be showing tabs");
+
+  function checkTabsPage(tabsShownCount, showMoreLabel) {
+    let tabList = document.getElementById("PanelUI-remotetabs-tabslist");
+    let node = tabList.firstChild;
+    is(node.getAttribute("itemtype"), "client", "node is a client entry");
+    is(node.textContent, "My Desktop", "correct client");
+    for (let i = 0; i < tabsShownCount; i++) {
+      node = node.nextSibling;
+      is(node.getAttribute("itemtype"), "tab", "node is a tab");
+      is(node.getAttribute("label"), "Tab #" + (i + 1), "the tab is the correct one");
+    }
+    let showMoreButton;
+    if (showMoreLabel) {
+      node = showMoreButton = node.nextSibling;
+      is(node.getAttribute("itemtype"), "showmorebutton", "node is a show more button");
+      is(node.getAttribute("label"), showMoreLabel);
+    }
+    node = node.nextSibling;
+    is(node, null, "no more entries");
+
+    return showMoreButton;
+  }
+
+  let showMoreButton;
+  function clickShowMoreButton() {
+    let promise = promiseObserverNotified("synced-tabs-menu:test:tabs-updated");
+    showMoreButton.click();
+    return promise;
+  }
+
+  showMoreButton = checkTabsPage(25, "Show More");
+  yield clickShowMoreButton();
+
+  showMoreButton = checkTabsPage(50, "Show More");
+  yield clickShowMoreButton();
+
+  showMoreButton = checkTabsPage(72, "Show All");
+  yield clickShowMoreButton();
+
+  checkTabsPage(77, null);
+
+  yield panelUIHide();
+});

--- a/browser/components/extensions/ext-browserAction.js
+++ b/browser/components/extensions/ext-browserAction.js
@@ -33,17 +33,24 @@ function isAncestorOrSelf(target, node) 
     if (node === target) {
       return true;
     }
   }
   return false;
 }
 
 // WeakMap[Extension -> BrowserAction]
-var browserActionMap = new WeakMap();
+const browserActionMap = new WeakMap();
+
+const browserAreas = {
+  "navbar": CustomizableUI.AREA_NAVBAR,
+  "menupanel": CustomizableUI.AREA_PANEL,
+  "tabstrip": CustomizableUI.AREA_TABSTRIP,
+  "personaltoolbar": CustomizableUI.AREA_BOOKMARKS,
+};
 
 // Responsible for the browser_action section of the manifest as well
 // as the associated popup.
 function BrowserAction(options, extension) {
   this.extension = extension;
 
   let widgetId = makeWidgetId(extension.id);
   this.id = `${widgetId}-browser-action`;
@@ -57,16 +64,17 @@ function BrowserAction(options, extensio
 
   this.defaults = {
     enabled: true,
     title: options.default_title || extension.name,
     badgeText: "",
     badgeBackgroundColor: null,
     icon: IconDetails.normalize({path: options.default_icon}, extension),
     popup: options.default_popup || "",
+    area: browserAreas[options.default_area || "navbar"],
   };
 
   this.browserStyle = options.browser_style || false;
   if (options.browser_style === null) {
     this.extension.logger.warn("Please specify whether you want browser_style " +
                                "or not in your browser_action options.");
   }
 
@@ -80,17 +88,17 @@ BrowserAction.prototype = {
   build() {
     let widget = CustomizableUI.createWidget({
       id: this.id,
       viewId: this.viewId,
       type: "view",
       removable: true,
       label: this.defaults.title || this.extension.name,
       tooltiptext: this.defaults.title || "",
-      defaultArea: CustomizableUI.AREA_NAVBAR,
+      defaultArea: this.defaults.area,
 
       onBeforeCreated: document => {
         let view = document.createElementNS(XUL_NS, "panelview");
         view.id = this.viewId;
         view.setAttribute("flex", "1");
 
         document.getElementById("PanelUI-multiView").appendChild(view);
         document.addEventListener("popupshowing", this);

--- a/browser/components/extensions/schemas/browser_action.json
+++ b/browser/components/extensions/schemas/browser_action.json
@@ -26,16 +26,22 @@
                 "type": "string",
                 "format": "relativeUrl",
                 "optional": true,
                 "preprocess": "localize"
               },
               "browser_style": {
                 "type": "boolean",
                 "optional": true
+              },
+              "default_area": {
+                "description": "Defines the location the browserAction will appear by default.  The default location is navbar.",
+                "type": "string",
+                "enum": ["navbar", "menupanel", "tabstrip", "personaltoolbar"],
+                "optional": true
               }
             },
             "optional": true
           }
         }
       }
     ]
   },

--- a/browser/components/extensions/test/browser/browser-common.ini
+++ b/browser/components/extensions/test/browser/browser-common.ini
@@ -19,16 +19,17 @@ support-files =
   file_dummy.html
   file_inspectedwindow_reload_target.sjs
   file_serviceWorker.html
   serviceWorker.js
   searchSuggestionEngine.xml
   searchSuggestionEngine.sjs
   ../../../../../toolkit/components/extensions/test/mochitest/head_webrequest.js
 
+[browser_ext_browserAction_area.js]
 [browser_ext_browserAction_context.js]
 [browser_ext_browserAction_disabled.js]
 [browser_ext_browserAction_pageAction_icon.js]
 [browser_ext_browserAction_pageAction_icon_permissions.js]
 [browser_ext_browserAction_popup.js]
 [browser_ext_browserAction_popup_preload.js]
 [browser_ext_browserAction_popup_resize.js]
 [browser_ext_browserAction_simple.js]

new file mode 100644
--- /dev/null
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_area.js
@@ -0,0 +1,49 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+var browserAreas = {
+  "navbar": CustomizableUI.AREA_NAVBAR,
+  "menupanel": CustomizableUI.AREA_PANEL,
+  "tabstrip": CustomizableUI.AREA_TABSTRIP,
+  "personaltoolbar": CustomizableUI.AREA_BOOKMARKS,
+};
+
+function* testInArea(area) {
+  let manifest = {
+    "browser_action": {
+      "browser_style": true,
+    },
+  };
+  if (area) {
+    manifest.browser_action.default_area = area;
+  }
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest,
+  });
+  yield extension.startup();
+  let widget = getBrowserActionWidget(extension);
+  let placement = CustomizableUI.getPlacementOfWidget(widget.id);
+  is(placement && placement.area, browserAreas[area || "navbar"], `widget located in correct area`);
+  yield extension.unload();
+}
+
+add_task(function* testBrowserActionDefaultArea() {
+  yield testInArea();
+});
+
+add_task(function* testBrowserActionInToolbar() {
+  yield testInArea("navbar");
+});
+
+add_task(function* testBrowserActionInMenuPanel() {
+  yield testInArea("menupanel");
+});
+
+add_task(function* testBrowserActionInTabStrip() {
+  yield testInArea("tabstrip");
+});
+
+add_task(function* testBrowserActionInPersonalToolbar() {
+  yield testInArea("personaltoolbar");
+});

--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -383,17 +383,17 @@ this.SessionStore = {
    *        The browser state for which we remove worth-saving tabs.
    *        The given object will be modified.
    */
   keepOnlyWorthSavingTabs: function (aState) {
     for (let i = aState.windows.length - 1; i >= 0; i--) {
       let win = aState.windows[i];
       for (let j = win.tabs.length - 1; j >= 0; j--) {
         let tab = win.tabs[j];
-        if (!SessionStoreInternal._shouldSaveTabState(tab)) {
+        if (!SessionStoreInternal._shouldSaveTab(tab)) {
           win.tabs.splice(j, 1);
           if (win.selected > j) {
             win.selected--;
           }
         }
       }
       if (!win.tabs.length) {
         aState.windows.splice(i, 1);
@@ -4193,21 +4193,40 @@ var SessionStoreInternal = {
   _shouldSaveTabState: function ssi_shouldSaveTabState(aTabState) {
     // If the tab has only a transient about: history entry, no other
     // session history, and no userTypedValue, then we don't actually want to
     // store this tab's data.
     return aTabState.entries.length &&
            !(aTabState.entries.length == 1 &&
                 (aTabState.entries[0].url == "about:blank" ||
                  aTabState.entries[0].url == "about:newtab" ||
+                 aTabState.entries[0].url == "about:printpreview" ||
                  aTabState.entries[0].url == "about:privatebrowsing") &&
                  !aTabState.userTypedValue);
   },
 
   /**
+   * Determine if the tab state we're passed is something we should keep to be
+   * reopened at session restore. This is used when we are saving the current
+   * session state to disk. This method is very similar to _shouldSaveTabState,
+   * however, "about:blank" and "about:newtab" tabs will still be saved to disk.
+   *
+   * @param aTabState
+   *        The current tab state
+   * @returns boolean
+   */
+  _shouldSaveTab: function ssi_shouldSaveTab(aTabState) {
+    // If the tab has one of the following transient about: history entry,
+    // then we don't actually want to write this tab's data to disk.
+    return aTabState.entries.length &&
+           !(aTabState.entries[0].url == "about:printpreview" ||
+             aTabState.entries[0].url == "about:privatebrowsing");
+  },
+
+  /**
    * This is going to take a state as provided at startup (via
    * nsISessionStartup.state) and split it into 2 parts. The first part
    * (defaultState) will be a state that should still be restored at startup,
    * while the second part (state) is a state that should be saved for later.
    * defaultState will be comprised of windows with only pinned tabs, extracted
    * from state. It will contain the cookies that go along with the history
    * entries in those tabs. It will also contain window position information.
    *

--- a/browser/confvars.sh
+++ b/browser/confvars.sh
@@ -50,17 +50,16 @@ MOZ_OFFICIAL_BRANDING_DIRECTORY=browser/
 MOZ_APP_ID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}
 # This should usually be the same as the value MAR_CHANNEL_ID.
 # If more than one ID is needed, then you should use a comma separated list
 # of values.
 ACCEPTED_MAR_CHANNEL_IDS=firefox-mozilla-central
 # The MAR_CHANNEL_ID must not contain the following 3 characters: ",\t "
 MAR_CHANNEL_ID=firefox-mozilla-central
 MOZ_PROFILE_MIGRATOR=1
-MOZ_WEBGL_CONFORMANT=1
 MOZ_JSDOWNLOADS=1
 MOZ_RUST_MP4PARSE=1
 
 # Enable checking that add-ons are signed by the trusted root
 MOZ_ADDON_SIGNING=1
 
 # Include the DevTools client, not just the server (which is the default)
 MOZ_DEVTOOLS=all

deleted file mode 100644
--- a/browser/extensions/disableSHA1rollout/README.md
+++ /dev/null
@@ -1,99 +0,0 @@
-This system add-on is a follow-up to the MITM prevalence experiment. The purpose
-is to facilitate rolling out the disabling of SHA-1 in signatures on
-certificates issued by publicly-trusted roots. When installed, this add-on will
-perform a number of checks to determine if it should change the preference that
-controls the SHA-1 policy. First, this should only apply to users on the beta
-update channel. It should also only apply to users who have not otherwise
-changed the policy to always allow or always forbid SHA-1. Additionally, it
-must double-check that the user is not affected by a TLS intercepting proxy
-using a publicly-trusted root. If these checks pass, the add-on will divide the
-population into a test group and a control group (starting on a 10%/90% split).
-The test group will have the policy changed. After doing this, a telemetry
-payload is reported with the following values:
-
-* cohortName -- the name of the group this user is in:
-  1. "notSafeToDisableSHA1" if the user is behind a MITM proxy using a
-     publicly-trusted root
-  2. "optedOut" if the user already set the SHA-1 policy to always allow or
-     always forbid
-  3. "optedIn" if the user already set the SHA-1 policy to only allow for
-     non-built-in roots
-  4. "test" if the user is in the test cohort (and SHA-1 will be disabled)
-  5. "control" if the user is not in the test cohort
-* errorCode -- 0 for successful connections, some PR error code otherwise
-* error -- a short description of one of four error conditions encountered, if
-  applicable, and an empty string otherwise:
-  1. "timeout" if the connection to telemetry.mozilla.org timed out
-  2. "user override" if the user has stored a permanent certificate exception
-     override for telemetry.mozilla.org (due to technical limitations, we can't
-     gather much information in this situation)
-  3. "certificate reverification" if re-building the certificate chain after
-     connecting failed for some reason (unfortunately this step is necessary
-     due to technical limitations)
-  4. "connection error" if the connection to telemetry.mozilla.org failed for
-     another reason
-* chain -- a list of dictionaries each corresponding to a certificate in the
-  verified certificate chain, if it was successfully constructed. The first
-  entry is the end-entity certificate. The last entry is the root certificate.
-  This will be empty if the connection failed or if reverification failed. Each
-  element in the list contains the following values:
-  * sha256Fingerprint -- a hex string representing the SHA-256 hash of the
-    certificate
-  * isBuiltInRoot -- true if the certificate is a trust anchor in the web PKI,
-    false otherwise
-  * signatureAlgorithm -- a description of the algorithm used to sign the
-    certificate. Will be one of "md2WithRSAEncryption", "md5WithRSAEncryption",
-    "sha1WithRSAEncryption", "sha256WithRSAEncryption",
-    "sha384WithRSAEncryption", "sha512WithRSAEncryption", "ecdsaWithSHA1",
-    "ecdsaWithSHA224", "ecdsaWithSHA256", "ecdsaWithSHA384", "ecdsaWithSHA512",
-    or "unknown".
-* disabledSHA1 -- true if SHA-1 was disabled, false otherwise
-* didNotDisableSHA1Because -- a short string describing why SHA-1 could not be
-    disabled, if applicable. Reasons are limited to:
-    1. "MITM" if the user is behind a TLS intercepting proxy using a
-       publicly-trusted root
-    2. "connection error" if there was an error connecting to
-       telemetry.mozilla.org
-    3. "code error" if some inconsistent state was detected, and it was
-       determined that the experiment should not attempt to change the
-       preference
-    4. "preference:userReset" if the user reset the SHA-1 policy after it had
-       been changed by this add-on
-    5. "preference:allow" if the user had already configured Firefox to always
-       accept SHA-1 signatures
-    6. "preference:forbid" if the user had already configured Firefox to always
-       forbid SHA-1 signatures
-
-For a connection not intercepted by a TLS proxy and where the user is in the
-test cohort, the expected result will be:
-
-    { "cohortName": "test",
-      "errorCode": 0,
-      "error": "",
-      "chain": [
-        { "sha256Fingerprint": "197feaf3faa0f0ad637a89c97cb91336bfc114b6b3018203cbd9c3d10c7fa86c",
-          "isBuiltInRoot": false,
-          "signatureAlgorithm": "sha256WithRSAEncryption"
-        },
-        { "sha256Fingerprint": "154c433c491929c5ef686e838e323664a00e6a0d822ccc958fb4dab03e49a08f",
-          "isBuiltInRoot": false,
-          "signatureAlgorithm": "sha256WithRSAEncryption"
-        },
-        { "sha256Fingerprint": "4348a0e9444c78cb265e058d5e8944b4d84f9662bd26db257f8934a443c70161",
-          "isBuiltInRoot": true,
-          "signatureAlgorithm": "sha1WithRSAEncryption"
-        }
-      ],
-      "disabledSHA1": true,
-      "didNotDisableSHA1Because": ""
-    }
-
-When this result is encountered, the user's preferences are updated to disable
-SHA-1 in signatures on certificates issued by publicly-trusted roots.
-Similarly, if the user is behind a TLS intercepting proxy but the root
-certificate is not part of the public web PKI, we can also disable SHA-1 in
-signatures on certificates issued by publicly-trusted roots.
-
-If the user has already indicated in their preferences that they will always
-accept SHA-1 in signatures or that they will never accept SHA-1 in signatures,
-then the preference is not changed.

deleted file mode 100644
--- a/browser/extensions/disableSHA1rollout/bootstrap.js
+++ /dev/null
@@ -1,306 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* 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/. */
-"use strict";
-
-const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
-
-Cu.import("resource://gre/modules/Preferences.jsm");
-Cu.import("resource://gre/modules/Services.jsm");
-Cu.import("resource://gre/modules/UpdateUtils.jsm");
-Cu.import("resource://gre/modules/TelemetryController.jsm");
-
- // Percentage of the population to attempt to disable SHA-1 for, by channel.
-const TEST_THRESHOLD = {
-  beta: 0.1, // 10%
-};
-
-const PREF_COHORT_SAMPLE = "disableSHA1.rollout.cohortSample";
-const PREF_COHORT_NAME = "disableSHA1.rollout.cohort";
-const PREF_SHA1_POLICY = "security.pki.sha1_enforcement_level";
-const PREF_SHA1_POLICY_SET_BY_ADDON = "disableSHA1.rollout.policySetByAddOn";
-const PREF_SHA1_POLICY_RESET_BY_USER = "disableSHA1.rollout.userResetPref";
-
-const SHA1_MODE_ALLOW = 0;
-const SHA1_MODE_FORBID = 1;
-const SHA1_MODE_IMPORTED_ROOTS_ONLY = 3;
-const SHA1_MODE_CURRENT_DEFAULT = 4;
-
-function startup() {
-  Preferences.observe(PREF_SHA1_POLICY, policyPreferenceChanged);
-}
-
-function install() {
-  let updateChannel = UpdateUtils.getUpdateChannel(false);
-  if (updateChannel in TEST_THRESHOLD) {
-    makeRequest().then(defineCohort).catch((e) => console.error(e));
-  }
-}
-
-function policyPreferenceChanged() {
-  let currentPrefValue = Preferences.get(PREF_SHA1_POLICY,
-                                         SHA1_MODE_CURRENT_DEFAULT);
-  Preferences.reset(PREF_SHA1_POLICY_RESET_BY_USER);
-  if (currentPrefValue == SHA1_MODE_CURRENT_DEFAULT) {
-    Preferences.set(PREF_SHA1_POLICY_RESET_BY_USER, true);
-  }
-}
-
-function defineCohort(result) {
-  let userOptedOut = optedOut();
-  let userOptedIn = optedIn();
-  let shouldNotDisableSHA1Because = reasonToNotDisableSHA1(result);
-  let safeToDisableSHA1 = shouldNotDisableSHA1Because.length == 0;
-  let updateChannel = UpdateUtils.getUpdateChannel(false);
-  let testGroup = getUserSample() < TEST_THRESHOLD[updateChannel];
-
-  let cohortName;
-  if (!safeToDisableSHA1) {
-    cohortName = "notSafeToDisableSHA1";
-  } else if (userOptedOut) {
-    cohortName = "optedOut";
-  } else if (userOptedIn) {
-    cohortName = "optedIn";
-  } else if (testGroup) {
-    cohortName = "test";
-    Preferences.ignore(PREF_SHA1_POLICY, policyPreferenceChanged);
-    Preferences.set(PREF_SHA1_POLICY, SHA1_MODE_IMPORTED_ROOTS_ONLY);
-    Preferences.observe(PREF_SHA1_POLICY, policyPreferenceChanged);
-    Preferences.set(PREF_SHA1_POLICY_SET_BY_ADDON, true);
-  } else {
-    cohortName = "control";
-  }
-  Preferences.set(PREF_COHORT_NAME, cohortName);
-  reportTelemetry(result, cohortName, shouldNotDisableSHA1Because,
-                  cohortName == "test");
-}
-
-function shutdown(data, reason) {
-  Preferences.ignore(PREF_SHA1_POLICY, policyPreferenceChanged);
-}
-
-function uninstall() {
-}
-
-function getUserSample() {
-  let prefValue = Preferences.get(PREF_COHORT_SAMPLE, undefined);
-  let value = 0.0;
-
-  if (typeof(prefValue) == "string") {
-    value = parseFloat(prefValue, 10);
-    return value;
-  }
-
-  value = Math.random();
-
-  Preferences.set(PREF_COHORT_SAMPLE, value.toString().substr(0, 8));
-  return value;
-}
-
-function reportTelemetry(result, cohortName, didNotDisableSHA1Because,
-                         disabledSHA1) {
-  result.cohortName = cohortName;
-  result.disabledSHA1 = disabledSHA1;
-  if (cohortName == "optedOut") {
-    let userResetPref = Preferences.get(PREF_SHA1_POLICY_RESET_BY_USER, false);
-    let currentPrefValue = Preferences.get(PREF_SHA1_POLICY,
-                                           SHA1_MODE_CURRENT_DEFAULT);
-    if (userResetPref) {
-      didNotDisableSHA1Because = "preference:userReset";
-    } else if (currentPrefValue == SHA1_MODE_ALLOW) {
-      didNotDisableSHA1Because = "preference:allow";
-    } else {
-      didNotDisableSHA1Because = "preference:forbid";
-    }
-  }
-  result.didNotDisableSHA1Because = didNotDisableSHA1Because;
-  return TelemetryController.submitExternalPing("disableSHA1rollout", result,
-                                                {});
-}
-
-function optedIn() {
-  let policySetByAddOn = Preferences.get(PREF_SHA1_POLICY_SET_BY_ADDON, false);
-  let currentPrefValue = Preferences.get(PREF_SHA1_POLICY,
-                                         SHA1_MODE_CURRENT_DEFAULT);
-  return currentPrefValue == SHA1_MODE_IMPORTED_ROOTS_ONLY && !policySetByAddOn;
-}
-
-function optedOut() {
-  // Users can also opt-out by setting the policy to always allow or always
-  // forbid SHA-1, or by resetting the preference after this add-on has changed
-  // it (in that case, this will be reported the next time this add-on is
-  // updated).
-  let currentPrefValue = Preferences.get(PREF_SHA1_POLICY,
-                                         SHA1_MODE_CURRENT_DEFAULT);
-  let userResetPref = Preferences.get(PREF_SHA1_POLICY_RESET_BY_USER, false);
-  return currentPrefValue == SHA1_MODE_ALLOW ||
-         currentPrefValue == SHA1_MODE_FORBID ||
-         userResetPref;
-}
-
-function delocalizeAlgorithm(localizedString) {
-  let bundle = Services.strings.createBundle(
-    "chrome://pipnss/locale/pipnss.properties");
-  let algorithmStringIdsToOIDDescriptionMap = {
-    "CertDumpMD2WithRSA":                       "md2WithRSAEncryption",
-    "CertDumpMD5WithRSA":                       "md5WithRSAEncryption",
-    "CertDumpSHA1WithRSA":                      "sha1WithRSAEncryption",
-    "CertDumpSHA256WithRSA":                    "sha256WithRSAEncryption",
-    "CertDumpSHA384WithRSA":                    "sha384WithRSAEncryption",
-    "CertDumpSHA512WithRSA":                    "sha512WithRSAEncryption",
-    "CertDumpAnsiX962ECDsaSignatureWithSha1":   "ecdsaWithSHA1",
-    "CertDumpAnsiX962ECDsaSignatureWithSha224": "ecdsaWithSHA224",
-    "CertDumpAnsiX962ECDsaSignatureWithSha256": "ecdsaWithSHA256",
-    "CertDumpAnsiX962ECDsaSignatureWithSha384": "ecdsaWithSHA384",
-    "CertDumpAnsiX962ECDsaSignatureWithSha512": "ecdsaWithSHA512",
-  };
-
-  let description;
-  Object.keys(algorithmStringIdsToOIDDescriptionMap).forEach((l10nID) => {
-    let candidateLocalizedString = bundle.GetStringFromName(l10nID);
-    if (localizedString == candidateLocalizedString) {
-      description = algorithmStringIdsToOIDDescriptionMap[l10nID];
-    }
-  });
-  if (!description) {
-    return "unknown";
-  }
-  return description;
-}
-
-function getSignatureAlgorithm(cert) {
-  // Certificate  ::=  SEQUENCE  {
-  //      tbsCertificate       TBSCertificate,
-  //      signatureAlgorithm   AlgorithmIdentifier,
-  //      signatureValue       BIT STRING  }
-  let certificate = cert.ASN1Structure.QueryInterface(Ci.nsIASN1Sequence);
-  let signatureAlgorithm = certificate.ASN1Objects
-                                      .queryElementAt(1, Ci.nsIASN1Sequence);
-  // AlgorithmIdentifier  ::=  SEQUENCE  {
-  //      algorithm               OBJECT IDENTIFIER,
-  //      parameters              ANY DEFINED BY algorithm OPTIONAL  }
-
-  // If parameters is NULL (or empty), signatureAlgorithm won't be a container
-  // under this implementation. Just get its displayValue.
-  if (!signatureAlgorithm.isValidContainer) {
-    return signatureAlgorithm.displayValue;
-  }
-  let oid = signatureAlgorithm.ASN1Objects.queryElementAt(0, Ci.nsIASN1Object);
-  return oid.displayValue;
-}
-
-function processCertChain(chain) {
-  let output = [];
-  let enumerator = chain.getEnumerator();
-  while (enumerator.hasMoreElements()) {
-    let cert = enumerator.getNext().QueryInterface(Ci.nsIX509Cert);
-    output.push({
-      sha256Fingerprint: cert.sha256Fingerprint.replace(/:/g, "").toLowerCase(),
-      isBuiltInRoot: cert.isBuiltInRoot,
-      signatureAlgorithm: delocalizeAlgorithm(getSignatureAlgorithm(cert)),
-    });
-  }
-  return output;
-}
-
-class CertificateVerificationResult {
-  constructor(resolve) {
-    this.resolve = resolve;
-  }
-
-  verifyCertFinished(aPRErrorCode, aVerifiedChain, aEVStatus) {
-    let result = { errorCode: aPRErrorCode, error: "", chain: [] };
-    if (aPRErrorCode == 0) {
-      result.chain = processCertChain(aVerifiedChain);
-    } else {
-      result.error = "certificate reverification";
-    }
-    this.resolve(result);
-  }
-}
-
-function makeRequest() {
-  return new Promise((resolve) => {
-    let hostname = "telemetry.mozilla.org";
-    let req = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"]
-                .createInstance(Ci.nsIXMLHttpRequest);
-    req.open("GET", "https://" + hostname);
-    req.channel.loadFlags |= Ci.nsIRequest.LOAD_BYPASS_CACHE;
-    req.timeout = 30000;
-    req.addEventListener("error", (evt) => {
-      // If we can't connect to telemetry.mozilla.org, then how did we even
-      // download the experiment? In any case, we may still be able to get some
-      // information.
-      let result = { error: "connection error" };
-      if (evt.target.channel && evt.target.channel.securityInfo) {
-        let securityInfo = evt.target.channel.securityInfo
-                             .QueryInterface(Ci.nsITransportSecurityInfo);
-        if (securityInfo) {
-          result.errorCode = securityInfo.errorCode;
-        }
-        if (securityInfo && securityInfo.failedCertChain) {
-          result.chain = processCertChain(securityInfo.failedCertChain);
-        }
-      }
-      resolve(result);
-    });
-    req.addEventListener("timeout", (evt) => {
-      resolve({ error: "timeout" });
-    });
-    req.addEventListener("load", (evt) => {
-      let securityInfo = evt.target.channel.securityInfo
-                           .QueryInterface(Ci.nsITransportSecurityInfo);
-      if (securityInfo.securityState &
-          Ci.nsIWebProgressListener.STATE_CERT_USER_OVERRIDDEN) {
-        resolve({ error: "user override" });
-        return;
-      }
-      let sslStatus = securityInfo.QueryInterface(Ci.nsISSLStatusProvider)
-                        .SSLStatus;
-      let certdb = Cc["@mozilla.org/security/x509certdb;1"]
-                     .getService(Ci.nsIX509CertDB);
-      let result = new CertificateVerificationResult(resolve);
-      // Unfortunately, we don't have direct access to the verified certificate
-      // chain as built by the AuthCertificate hook, so we have to re-build it
-      // here. In theory we are likely to get the same result.
-      certdb.asyncVerifyCertAtTime(sslStatus.serverCert,
-                                   2, // certificateUsageSSLServer
-                                   0, // flags
-                                   hostname,
-                                   Date.now() / 1000,
-                                   result);
-    });
-    req.send();
-  });
-}
-
-// As best we know, it is safe to disable SHA1 if the connection was successful
-// and either the connection was MITM'd by a root not in the public PKI or the
-// chain is part of the public PKI and is the one served by the real
-// telemetry.mozilla.org.
-// This will return a short string description of why it might not be safe to
-// disable SHA1 or an empty string if it is safe to disable SHA1.
-function reasonToNotDisableSHA1(result) {
-  if (!("errorCode" in result) || result.errorCode != 0) {
-    return "connection error";
-  }
-  if (!("chain" in result)) {
-    return "code error";
-  }
-  if (!result.chain[result.chain.length - 1].isBuiltInRoot) {
-    return "";
-  }
-  if (result.chain.length != 3) {
-    return "MITM";
-  }
-  const kEndEntityFingerprint = "197feaf3faa0f0ad637a89c97cb91336bfc114b6b3018203cbd9c3d10c7fa86c";
-  const kIntermediateFingerprint = "154c433c491929c5ef686e838e323664a00e6a0d822ccc958fb4dab03e49a08f";
-  const kRootFingerprint = "4348a0e9444c78cb265e058d5e8944b4d84f9662bd26db257f8934a443c70161";
-  if (result.chain[0].sha256Fingerprint != kEndEntityFingerprint ||
-      result.chain[1].sha256Fingerprint != kIntermediateFingerprint ||
-      result.chain[2].sha256Fingerprint != kRootFingerprint) {
-    return "MITM";
-  }
-  return "";
-}

deleted file mode 100644
--- a/browser/extensions/disableSHA1rollout/install.rdf.in
+++ /dev/null
@@ -1,32 +0,0 @@
-<?xml version="1.0"?>
-<!-- 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/. -->
-
-#filter substitution
-
-<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
-
-  <Description about="urn:mozilla:install-manifest">
-    <em:id>disableSHA1rollout@mozilla.org</em:id>
-    <em:version>1.0</em:version>
-    <em:type>2</em:type>
-    <em:bootstrap>true</em:bootstrap>
-    <em:multiprocessCompatible>true</em:multiprocessCompatible>
-
-    <!-- Target Application this theme can install into,
-        with minimum and maximum supported versions. -->
-    <em:targetApplication>
-      <Description>
-        <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
-        <em:minVersion>@MOZ_APP_VERSION@</em:minVersion>
-        <em:maxVersion>@MOZ_APP_MAXVERSION@</em:maxVersion>
-      </Description>
-    </em:targetApplication>
-
-    <!-- Front End MetaData -->
-    <em:name>SHA-1 deprecation staged rollout</em:name>
-    <em:description>Staged rollout deprecating SHA-1 in certificate signatures.</em:description>
-  </Description>
-</RDF>

deleted file mode 100644
--- a/browser/extensions/disableSHA1rollout/moz.build
+++ /dev/null
@@ -1,16 +0,0 @@
-# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-DEFINES['MOZ_APP_VERSION'] = CONFIG['MOZ_APP_VERSION']
-DEFINES['MOZ_APP_MAXVERSION'] = CONFIG['MOZ_APP_MAXVERSION']
-
-FINAL_TARGET_FILES.features['disableSHA1rollout@mozilla.org'] += [
-  'bootstrap.js'
-]
-
-FINAL_TARGET_PP_FILES.features['disableSHA1rollout@mozilla.org'] += [
-  'install.rdf.in'
-]

--- a/browser/extensions/formautofill/FormAutofillContent.jsm
+++ b/browser/extensions/formautofill/FormAutofillContent.jsm
@@ -266,19 +266,20 @@ var FormAutofillContent = {
 
     Services.cpmm.addMessageListener("FormAutofill:enabledStatus", (result) => {
       if (result.data) {
         ProfileAutocomplete.ensureRegistered();
       } else {
         ProfileAutocomplete.ensureUnregistered();
       }
     });
-    Services.cpmm.sendAsyncMessage("FormAutofill:getEnabledStatus");
-    // TODO: use initialProcessData:
-    // Services.cpmm.initialProcessData.autofillEnabled
+
+    if (Services.cpmm.initialProcessData.autofillEnabled) {
+      ProfileAutocomplete.ensureRegistered();
+    }
   },
 
   /**
    * Get the input's information from cache which is created after page identified.
    *
    * @param {HTMLInputElement} element Focused input which triggered profile searching
    * @returns {Object|null}
    *          Return target input's information that cloned from content cache

--- a/browser/extensions/formautofill/FormAutofillParent.jsm
+++ b/browser/extensions/formautofill/FormAutofillParent.jsm
@@ -75,21 +75,20 @@ FormAutofillParent.prototype = {
     this._profileStore = new ProfileStorage(storePath);
     this._profileStore.initialize();
 
     Services.obs.addObserver(this, "advanced-pane-loaded", false);
 
     // Observing the pref and storage changes
     Services.prefs.addObserver(ENABLED_PREF, this, false);
     Services.obs.addObserver(this, "formautofill-storage-changed", false);
-    this._enabled = this._getStatus();
+
     // Force to trigger the onStatusChanged function for setting listeners properly
     // while initizlization
-    this._onStatusChanged();
-    Services.ppmm.addMessageListener("FormAutofill:getEnabledStatus", this);
+    this._setStatus(this._getStatus());
   },
 
   observe(subject, topic, data) {
     log.debug("observe:", topic, "with data:", data);
     switch (topic) {
       case "advanced-pane-loaded": {
         let formAutofillPreferences = new FormAutofillPreferences();
         let document = subject.document;
@@ -99,32 +98,30 @@ FormAutofillParent.prototype = {
         parentNode.insertBefore(prefGroup, insertBeforeNode);
         break;
       }
 
       case "nsPref:changed": {
         // Observe pref changes and update _enabled cache if status is changed.
         let currentStatus = this._getStatus();
         if (currentStatus !== this._enabled) {
-          this._enabled = currentStatus;
-          this._onStatusChanged();
+          this._setStatus(currentStatus);
         }
         break;
       }
 
       case "formautofill-storage-changed": {
         // Early exit if the action is not "add" nor "remove"
         if (data != "add" && data != "remove") {
           break;
         }
 
         let currentStatus = this._getStatus();
         if (currentStatus !== this._enabled) {
-          this._enabled = currentStatus;
-          this._onStatusChanged();
+          this._setStatus(currentStatus);
         }
         break;
       }
 
       default: {
         throw new Error(`FormAutofillParent: Unexpected topic observed: ${topic}`);
       }
     }
@@ -138,16 +135,19 @@ FormAutofillParent.prototype = {
     log.debug("_onStatusChanged: Status changed to", this._enabled);
     if (this._enabled) {
       Services.ppmm.addMessageListener("FormAutofill:GetProfiles", this);
     } else {
       Services.ppmm.removeMessageListener("FormAutofill:GetProfiles", this);
     }
 
     Services.ppmm.broadcastAsyncMessage("FormAutofill:enabledStatus", this._enabled);
+    // Sync process data autofillEnabled to make sure the value up to date
+    // no matter when the new content process is initialized.
+    Services.ppmm.initialProcessData.autofillEnabled = this._enabled;
   },
 
   /**
    * Query pref and storage status to determine the overall status for
    * form autofill feature.
    *
    * @returns {boolean} status of form autofill feature
    */
@@ -155,31 +155,37 @@ FormAutofillParent.prototype = {
     if (!Services.prefs.getBoolPref(ENABLED_PREF)) {
       return false;
     }
 
     return this._profileStore.getAll().length > 0;
   },
 
   /**
+   * Set status and trigger _onStatusChanged.
+   *
+   * @param {boolean} newStatus The latest status we want to set for _enabled
+   */
+  _setStatus(newStatus) {
+    this._enabled = newStatus;
+    this._onStatusChanged();
+  },
+
+  /**
    * Handles the message coming from FormAutofillContent.
    *
    * @param   {string} message.name The name of the message.
    * @param   {object} message.data The data of the message.
    * @param   {nsIFrameMessageManager} message.target Caller's message manager.
    */
   receiveMessage({name, data, target}) {
     switch (name) {
       case "FormAutofill:GetProfiles":
         this._getProfiles(data, target);
         break;
-      case "FormAutofill:getEnabledStatus":
-        Services.ppmm.broadcastAsyncMessage("FormAutofill:enabledStatus",
-                                            this._enabled);
-        break;
     }
   },
 
   /**
    * Returns the instance of ProfileStorage. To avoid syncing issues, anyone
    * who needs to access the profile should request the instance by this instead
    * of creating a new one.
    *

--- a/browser/extensions/formautofill/ProfileAutoCompleteResult.jsm
+++ b/browser/extensions/formautofill/ProfileAutoCompleteResult.jsm
@@ -64,21 +64,21 @@ ProfileAutoCompleteResult.prototype = {
 
   // An array of primary and secondary labels for each profiles.
   _popupLabels: null,
 
   /**
    * @returns {number} The number of results
    */
   get matchCount() {
-    return this._matchingProfiles.length;
+    return this._popupLabels.length;
   },
 
   _checkIndexBounds(index) {
-    if (index < 0 || index >= this._matchingProfiles.length) {
+    if (index < 0 || index >= this._popupLabels.length) {
       throw Components.Exception("Index out of range.", Cr.NS_ERROR_ILLEGAL_VALUE);
     }
   },
 
   /**
    * Get the secondary label based on the focused field name and related field names
    * in the same form.
    * @param   {string} focusedFieldName The field name of the focused input
@@ -118,17 +118,20 @@ ProfileAutoCompleteResult.prototype = {
         return profile[currentFieldName];
       }
     }
 
     return ""; // Nothing matched.
   },
 
   _generateLabels(focusedFieldName, allFieldNames, profiles) {
-    return profiles.map(profile => {
+    // Skip results without a primary label.
+    return profiles.filter(profile => {
+      return !!profile[focusedFieldName];
+    }).map(profile => {
       return {
         primary: profile[focusedFieldName],
         secondary: this._getSecondaryLabel(focusedFieldName,
                                            allFieldNames,
                                            profile),
       };
     });
   },

--- a/browser/extensions/formautofill/test/unit/test_enabledStatus.js
+++ b/browser/extensions/formautofill/test/unit/test_enabledStatus.js
@@ -3,60 +3,62 @@
  */
 
 "use strict";
 
 Cu.import("resource://formautofill/FormAutofillParent.jsm");
 
 add_task(function* test_enabledStatus_init() {
   let formAutofillParent = new FormAutofillParent();
-  sinon.spy(formAutofillParent, "_onStatusChanged");
+  sinon.spy(formAutofillParent, "_setStatus");
 
   // Default status is false before initialization
   do_check_eq(formAutofillParent._enabled, false);
+  do_check_eq(Services.ppmm.initialProcessData.autofillEnabled, undefined);
 
   formAutofillParent.init();
-  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+  do_check_eq(formAutofillParent._setStatus.called, true);
+  do_check_eq(Services.ppmm.initialProcessData.autofillEnabled, false);
 
   formAutofillParent._uninit();
 });
 
 add_task(function* test_enabledStatus_observe() {
   let formAutofillParent = new FormAutofillParent();
   sinon.stub(formAutofillParent, "_getStatus");
-  sinon.spy(formAutofillParent, "_onStatusChanged");
+  sinon.spy(formAutofillParent, "_setStatus");
 
   // _enabled = _getStatus() => No need to trigger onStatusChanged
   formAutofillParent._enabled = true;
   formAutofillParent._getStatus.returns(true);
   formAutofillParent.observe(null, "nsPref:changed", "browser.formautofill.enabled");
-  do_check_eq(formAutofillParent._onStatusChanged.called, false);
+  do_check_eq(formAutofillParent._setStatus.called, false);
 
   // _enabled != _getStatus() => Need to trigger onStatusChanged
   formAutofillParent._getStatus.returns(false);
   formAutofillParent.observe(null, "nsPref:changed", "browser.formautofill.enabled");
-  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+  do_check_eq(formAutofillParent._setStatus.called, true);
 
   // profile added => Need to trigger onStatusChanged
   formAutofillParent._getStatus.returns(!formAutofillParent._enabled);
-  formAutofillParent._onStatusChanged.reset();
+  formAutofillParent._setStatus.reset();
   formAutofillParent.observe(null, "formautofill-storage-changed", "add");
-  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+  do_check_eq(formAutofillParent._setStatus.called, true);
 
   // profile removed => Need to trigger onStatusChanged
   formAutofillParent._getStatus.returns(!formAutofillParent._enabled);
-  formAutofillParent._onStatusChanged.reset();
+  formAutofillParent._setStatus.reset();
   formAutofillParent.observe(null, "formautofill-storage-changed", "remove");
-  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+  do_check_eq(formAutofillParent._setStatus.called, true);
 
   // profile updated => no need to trigger onStatusChanged
   formAutofillParent._getStatus.returns(!formAutofillParent._enabled);
-  formAutofillParent._onStatusChanged.reset();
+  formAutofillParent._setStatus.reset();
   formAutofillParent.observe(null, "formautofill-storage-changed", "update");
-  do_check_eq(formAutofillParent._onStatusChanged.called, false);
+  do_check_eq(formAutofillParent._setStatus.called, false);
 });
 
 add_task(function* test_enabledStatus_getStatus() {
   let formAutofillParent = new FormAutofillParent();
   do_register_cleanup(function cleanup() {
     Services.prefs.clearUserPref("browser.formautofill.enabled");
   });
 
@@ -77,8 +79,24 @@ add_task(function* test_enabledStatus_ge
   // pref is enabled and profile is not empty.
   Services.prefs.setBoolPref("browser.formautofill.enabled", true);
   do_check_eq(formAutofillParent._getStatus(), true);
 
   // pref is disabled and profile is not empty.
   Services.prefs.setBoolPref("browser.formautofill.enabled", false);
   do_check_eq(formAutofillParent._getStatus(), false);
 });
+
+add_task(function* test_enabledStatus_setStatus() {
+  let formAutofillParent = new FormAutofillParent();
+  sinon.spy(formAutofillParent, "_onStatusChanged");
+
+  formAutofillParent._setStatus(true);
+  do_check_eq(formAutofillParent._enabled, true);
+  do_check_eq(Services.ppmm.initialProcessData.autofillEnabled, true);
+  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+
+  formAutofillParent._onStatusChanged.reset();
+  formAutofillParent._setStatus(false);
+  do_check_eq(formAutofillParent._enabled, false);
+  do_check_eq(Services.ppmm.initialProcessData.autofillEnabled, false);
+  do_check_eq(formAutofillParent._onStatusChanged.called, true);
+});

--- a/browser/extensions/formautofill/test/unit/test_profileAutocompleteResult.js
+++ b/browser/extensions/formautofill/test/unit/test_profileAutocompleteResult.js
@@ -7,21 +7,27 @@ let matchingProfiles = [{
   organization: "Sesame Street",
   "street-address": "123 Sesame Street.",
   tel: "1-345-345-3456.",
 }, {
   guid: "test-guid-2",
   organization: "Mozilla",
   "street-address": "331 E. Evelyn Avenue",
   tel: "1-650-903-0800",
+}, {
+  guid: "test-guid-3",
+  organization: "",
+  "street-address": "321, No Name St.",
+  tel: "1-000-000-0000",
 }];
 
 let allFieldNames = ["street-address", "organization", "tel"];
 
 let testCases = [{
+  description: "Focus on an `organization` field",
   options: {},
   matchingProfiles,
   allFieldNames,
   searchString: "",
   fieldName: "organization",
   expected: {
     searchResult: Ci.nsIAutoCompleteResult.RESULT_SUCCESS,
     defaultIndex: 0,
@@ -41,16 +47,17 @@ let testCases = [{
       label: JSON.stringify({
         primary: "Mozilla",
         secondary: "331 E. Evelyn Avenue",
       }),
       image: "",
     }],
   },
 }, {
+  description: "Focus on an `tel` field",
   options: {},
   matchingProfiles,
   allFieldNames,
   searchString: "",
   fieldName: "tel",
   expected: {
     searchResult: Ci.nsIAutoCompleteResult.RESULT_SUCCESS,
     defaultIndex: 0,
@@ -67,19 +74,29 @@ let testCases = [{
       value: "1-650-903-0800",
       style: "autofill-profile",
       comment: JSON.stringify(matchingProfiles[1]),
       label: JSON.stringify({
         primary: "1-650-903-0800",
         secondary: "331 E. Evelyn Avenue",
       }),
       image: "",
+    }, {
+      value: "1-000-000-0000",
+      style: "autofill-profile",
+      comment: JSON.stringify(matchingProfiles[2]),
+      label: JSON.stringify({
+        primary: "1-000-000-0000",
+        secondary: "321, No Name St.",
+      }),
+      image: "",
     }],
   },
 }, {
+  description: "Focus on an `street-address` field",
   options: {},
   matchingProfiles,
   allFieldNames,
   searchString: "",
   fieldName: "street-address",
   expected: {
     searchResult: Ci.nsIAutoCompleteResult.RESULT_SUCCESS,
     defaultIndex: 0,
@@ -96,50 +113,62 @@ let testCases = [{
       value: "331 E. Evelyn Avenue",
       style: "autofill-profile",
       comment: JSON.stringify(matchingProfiles[1]),
       label: JSON.stringify({
         primary: "331 E. Evelyn Avenue",
         secondary: "Mozilla",
       }),
       image: "",
+    }, {
+      value: "321, No Name St.",
+      style: "autofill-profile",
+      comment: JSON.stringify(matchingProfiles[2]),
+      label: JSON.stringify({
+        primary: "321, No Name St.",
+        secondary: "1-000-000-0000",
+      }),
+      image: "",
     }],
   },
 }, {
+  description: "No matching profiles",
   options: {},
   matchingProfiles: [],
   allFieldNames,
   searchString: "",
   fieldName: "",
   expected: {
     searchResult: Ci.nsIAutoCompleteResult.RESULT_NOMATCH,
     defaultIndex: 0,
     items: [],
   },
 }, {
+  description: "Search with failure",
   options: {resultCode: Ci.nsIAutoCompleteResult.RESULT_FAILURE},
   matchingProfiles: [],
   allFieldNames,
   searchString: "",
   fieldName: "",
   expected: {
     searchResult: Ci.nsIAutoCompleteResult.RESULT_FAILURE,
     defaultIndex: 0,
     items: [],
   },
 }];
 
 add_task(function* test_all_patterns() {
-  testCases.forEach(pattern => {
-    let actual = new ProfileAutoCompleteResult(pattern.searchString,
-                                               pattern.fieldName,
-                                               pattern.allFieldNames,
-                                               pattern.matchingProfiles,
-                                               pattern.options);
-    let expectedValue = pattern.expected;
+  testCases.forEach(testCase => {
+    do_print("Starting testcase: " + testCase.description);
+    let actual = new ProfileAutoCompleteResult(testCase.searchString,
+                                               testCase.fieldName,
+                                               testCase.allFieldNames,
+                                               testCase.matchingProfiles,
+                                               testCase.options);
+    let expectedValue = testCase.expected;
     equal(actual.searchResult, expectedValue.searchResult);
     equal(actual.defaultIndex, expectedValue.defaultIndex);
     equal(actual.matchCount, expectedValue.items.length);
     expectedValue.items.forEach((item, index) => {
       equal(actual.getValueAt(index), item.value);
       equal(actual.getCommentAt(index), item.comment);
       equal(actual.getLabelAt(index), item.label);
       equal(actual.getStyleAt(index), item.style);

--- a/browser/extensions/moz.build
+++ b/browser/extensions/moz.build
@@ -1,17 +1,16 @@
 # -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
 # vim: set filetype=python:
 # 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/.
 
 DIRS += [
     'aushelper',
-    'disableSHA1rollout',
     'e10srollout',
     'pdfjs',
     'pocket',
     'webcompat',
     'shield-recipe-client',
 ]
 
 # Only include the following system add-ons if building Aurora or Nightly

--- a/browser/installer/package-manifest.in
+++ b/browser/installer/package-manifest.in
@@ -631,16 +631,17 @@
 
 ; [Default Preferences]
 ; All the pref files must be part of base to prevent migration bugs
 @RESPATH@/browser/@PREF_DIR@/firefox.js
 @RESPATH@/browser/@PREF_DIR@/firefox-branding.js
 @RESPATH@/greprefs.js
 @RESPATH@/defaults/autoconfig/prefcalls.js
 @RESPATH@/browser/defaults/permissions
+@RESPATH@/browser/defaults/blocklists
 
 ; Warning: changing the path to channel-prefs.js can cause bugs (Bug 756325)
 ; Technically this is an app pref file, but we are keeping it in the original
 ; gre location for now.
 @RESPATH@/defaults/pref/channel-prefs.js
 
 ; Services (gre) prefs
 @RESPATH@/defaults/pref/services-sync.js

--- a/browser/locales/en-US/chrome/browser/browser.dtd
+++ b/browser/locales/en-US/chrome/browser/browser.dtd
@@ -353,16 +353,24 @@ These should match what Safari and other
 <!ENTITY appMenuHistory.restoreSession.label "Restore Previous Session">
 <!ENTITY appMenuHistory.viewSidebar.label "View History Sidebar">
 <!ENTITY appMenuHelp.tooltip "Open Help Menu">
 
 <!ENTITY appMenuRemoteTabs.label "Synced Tabs">
 <!-- LOCALIZATION NOTE (appMenuRemoteTabs.notabs.label): This is shown beneath
      the name of a device when that device has no open tabs -->
 <!ENTITY appMenuRemoteTabs.notabs.label "No open tabs">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.showMore.label, appMenuRemoteTabs.showMore.tooltip):
+     This is shown after the tabs list if we can display more tabs by clicking on the button -->
+<!ENTITY appMenuRemoteTabs.showMore.label "Show More">
+<!ENTITY appMenuRemoteTabs.showMore.tooltip "Show more tabs from this device">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.showAll.label, appMenuRemoteTabs.showAll.tooltip):
+     This is shown after the tabs list if we can all the remaining tabs by clicking on the button -->
+<!ENTITY appMenuRemoteTabs.showAll.label "Show All">
+<!ENTITY appMenuRemoteTabs.showAll.tooltip "Show all tabs from this device">
 <!-- LOCALIZATION NOTE (appMenuRemoteTabs.tabsnotsyncing.label): This is shown
      when Sync is configured but syncing tabs is disabled. -->
 <!ENTITY appMenuRemoteTabs.tabsnotsyncing.label "Turn on tab syncing to view a list of tabs from your other devices.">
 <!-- LOCALIZATION NOTE (appMenuRemoteTabs.noclients.label): This is shown
      when Sync is configured but this appears to be the only device attached to
      the account. We also show links to download Firefox for android/ios. -->
 <!ENTITY appMenuRemoteTabs.noclients.title "No synced tabs… yet!">
 <!ENTITY appMenuRemoteTabs.noclients.subtitle "Want to see your tabs from other devices here?">

--- a/browser/locales/en-US/chrome/browser/preferences/preferences.properties
+++ b/browser/locales/en-US/chrome/browser/preferences/preferences.properties
@@ -202,22 +202,26 @@ removeAllSiteDataShown.label=Remove All 
 removeAllSiteDataShown.accesskey=e
 spaceAlert.learnMoreButton.label=Learn More
 spaceAlert.learnMoreButton.accesskey=L
 spaceAlert.over5GB.prefButton.label=Open Preferences
 spaceAlert.over5GB.prefButton.accesskey=O
 # LOCALIZATION NOTE (spaceAlert.over5GB.prefButtonWin.label): On Windows Preferences is called Options
 spaceAlert.over5GB.prefButtonWin.label=Open Options
 spaceAlert.over5GB.prefButtonWin.accesskey=O
-spaceAlert.over5GB.description=Firefox is running out of disk space. Website contents may not display properly. You can clear stored site data in Preferences > Advanced > Site Data.
-# LOCALIZATION NOTE (spaceAlert.over5GB.descriptionWin): On Windows Preferences is called Options
-spaceAlert.over5GB.descriptionWin=Firefox is running out of disk space. Website contents may not display properly. You can clear stored site data in Options > Advanced > Site Data.
+# LOCALIZATION NOTE (spaceAlert.over5GB.message): %S = brandShortName
+spaceAlert.over5GB.message=%S is running out of disk space. Website contents may not display properly. You can clear stored site data in Preferences > Advanced > Site Data.
+# LOCALIZATION NOTE (spaceAlert.over5GB.messageWin):
+# - On Windows Preferences is called Options
+# - %S = brandShortName
+spaceAlert.over5GB.messageWin=%S is running out of disk space. Website contents may not display properly. You can clear stored site data in Options > Advanced > Site Data.
 spaceAlert.under5GB.okButton.label=OK, Got it
 spaceAlert.under5GB.okButton.accesskey=K
-spaceAlert.under5GB.description=Firefox is running out of disk space. Website contents may not display properly. Visit “Learn More” to optimize your disk usage for better browsing experience.
+# LOCALIZATION NOTE (spaceAlert.under5GB.message): %S = brandShortName
+spaceAlert.under5GB.message=%S is running out of disk space. Website contents may not display properly. Visit “Learn More” to optimize your disk usage for better browsing experience.
 
 # LOCALIZATION NOTE (featureEnableRequiresRestart, featureDisableRequiresRestart, restartTitle): %S = brandShortName
 featureEnableRequiresRestart=%S must restart to enable this feature.
 featureDisableRequiresRestart=%S must restart to disable this feature.
 shouldRestartTitle=Restart %S
 okToRestartButton=Restart %S now
 revertNoRestartButton=Revert
 

--- a/browser/themes/shared/customizableui/panelUI.inc.css
+++ b/browser/themes/shared/customizableui/panelUI.inc.css
@@ -1238,29 +1238,29 @@ menuitem.panel-subview-footer@menuStateA
 
 .subviewbutton > .menu-accel-container {
   -moz-box-pack: start;
   margin-inline-start: 10px;
   margin-inline-end: auto;
   color: GrayText;
 }
 
-#PanelUI-remotetabs-tabslist > toolbarbutton,
+#PanelUI-remotetabs-tabslist > toolbarbutton[itemtype="tab"],
 #PanelUI-historyItems > toolbarbutton {
   list-style-image: url("chrome://mozapps/skin/places/defaultFavicon.png");
 }
 
 @media (min-resolution: 1.1dppx) {
-  #PanelUI-remotetabs-tabslist > toolbarbutton,
+  #PanelUI-remotetabs-tabslist > toolbarbutton[itemtype="tab"],
   #PanelUI-historyItems > toolbarbutton {
     list-style-image: url("chrome://mozapps/skin/places/defaultFavicon@2x.png");
   }
 }
 
-#PanelUI-remotetabs-tabslist > toolbarbutton > .toolbarbutton-icon,
+#PanelUI-remotetabs-tabslist > toolbarbutton[itemtype="tab"] > .toolbarbutton-icon,
 #PanelUI-recentlyClosedWindows > toolbarbutton > .toolbarbutton-icon,
 #PanelUI-recentlyClosedTabs > toolbarbutton > .toolbarbutton-icon,
 #PanelUI-historyItems > toolbarbutton > .toolbarbutton-icon {
   width: 16px;
   height: 16px;
 }
 
 toolbarbutton[panel-multiview-anchor="true"],

--- a/build/moz.configure/warnings.configure
+++ b/build/moz.configure/warnings.configure
@@ -73,19 +73,16 @@ check_and_add_gcc_warning('-Wimplicit-fa
 # --enable-warnings-as-errors is specified so that no unexpected fatal
 # warnings are produced.
 check_and_add_gcc_warning('-Werror=non-literal-null-conversion',
                           when='--enable-warnings-as-errors')
 
 # catches string literals used in boolean expressions
 check_and_add_gcc_warning('-Wstring-conversion')
 
-# catches inconsistent use of mutexes
-check_and_add_gcc_warning('-Wthread-safety')
-
 # we inline 'new' and 'delete' in mozalloc
 check_and_add_gcc_warning('-Wno-inline-new-delete', cxx_compiler)
 
 # Prevent the following GCC warnings from being treated as errors:
 # too many false positives
 check_and_add_gcc_warning('-Wno-error=maybe-uninitialized')
 
 # we don't want our builds held hostage when a platform-specific API

--- a/caps/moz.build
+++ b/caps/moz.build
@@ -36,16 +36,17 @@ EXPORTS.mozilla = [
 SOURCES += [
     # Compile this separately since nsExceptionHandler.h conflicts
     # with something from nsNullPrincipal.cpp.
     'BasePrincipal.cpp',
 ]
 
 UNIFIED_SOURCES += [
     'DomainPolicy.cpp',
+    'nsExpandedPrincipal.cpp',
     'nsJSPrincipals.cpp',
     'nsNullPrincipal.cpp',
     'nsNullPrincipalURI.cpp',
     'nsPrincipal.cpp',
     'nsScriptSecurityManager.cpp',
     'nsSystemPrincipal.cpp',
 ]
 

copy from caps/nsPrincipal.cpp
copy to caps/nsExpandedPrincipal.cpp
--- a/caps/nsPrincipal.cpp
+++ b/caps/nsExpandedPrincipal.cpp
@@ -1,471 +1,19 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 sw=2 et 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/. */
 
-#include "nsPrincipal.h"
-
-#include "mozIThirdPartyUtil.h"
-#include "nscore.h"
-#include "nsScriptSecurityManager.h"
-#include "nsString.h"
-#include "nsReadableUtils.h"
-#include "pratom.h"
-#include "nsIURI.h"
-#include "nsIURL.h"
-#include "nsIStandardURL.h"
-#include "nsIURIWithPrincipal.h"
-#include "nsJSPrincipals.h"
-#include "nsIEffectiveTLDService.h"
+#include "nsExpandedPrincipal.h"
 #include "nsIClassInfoImpl.h"
-#include "nsIProtocolHandler.h"
-#include "nsError.h"
-#include "nsIContentSecurityPolicy.h"
-#include "nsNetCID.h"
-#include "jswrapper.h"
-
-#include "mozilla/dom/nsCSPContext.h"
-#include "mozilla/dom/ScriptSettings.h"
-#include "mozilla/Preferences.h"
-#include "mozilla/HashFunctions.h"
 
 using namespace mozilla;
 
-static bool gCodeBasePrincipalSupport = false;
-
-static bool URIIsImmutable(nsIURI* aURI)
-{
-  nsCOMPtr<nsIMutable> mutableObj(do_QueryInterface(aURI));
-  bool isMutable;
-  return
-    mutableObj &&
-    NS_SUCCEEDED(mutableObj->GetMutable(&isMutable)) &&
-    !isMutable;
-}
-
-NS_IMPL_CLASSINFO(nsPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
-                  NS_PRINCIPAL_CID)
-NS_IMPL_QUERY_INTERFACE_CI(nsPrincipal,
-                           nsIPrincipal,
-                           nsISerializable)
-NS_IMPL_CI_INTERFACE_GETTER(nsPrincipal,
-                            nsIPrincipal,
-                            nsISerializable)
-
-// Called at startup:
-/* static */ void
-nsPrincipal::InitializeStatics()
-{
-  Preferences::AddBoolVarCache(&gCodeBasePrincipalSupport,
-                               "signed.applets.codebase_principal_support",
-                               false);
-}
-
-nsPrincipal::nsPrincipal()
-  : mCodebaseImmutable(false)
-  , mDomainImmutable(false)
-  , mInitialized(false)
-{ }
-
-nsPrincipal::~nsPrincipal()
-{
-  // let's clear the principal within the csp to avoid a tangling pointer
-  if (mCSP) {
-    static_cast<nsCSPContext*>(mCSP.get())->clearLoadingPrincipal();
-  }
-}
-
-nsresult
-nsPrincipal::Init(nsIURI *aCodebase, const OriginAttributes& aOriginAttributes)
-{
-  NS_ENSURE_STATE(!mInitialized);
-  NS_ENSURE_ARG(aCodebase);
-
-  mInitialized = true;
-
-  mCodebase = NS_TryToMakeImmutable(aCodebase);
-  mCodebaseImmutable = URIIsImmutable(mCodebase);
-  mOriginAttributes = aOriginAttributes;
-
-  return NS_OK;
-}
-
-nsresult
-nsPrincipal::GetScriptLocation(nsACString &aStr)
-{
-  return mCodebase->GetSpec(aStr);
-}
-
-nsresult
-nsPrincipal::GetOriginInternal(nsACString& aOrigin)
-{
-  if (!mCodebase) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsCOMPtr<nsIURI> origin = NS_GetInnermostURI(mCodebase);
-  if (!origin) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsAutoCString hostPort;
-
-  // chrome: URLs don't have a meaningful origin, so make
-  // sure we just get the full spec for them.
-  // XXX this should be removed in favor of the solution in
-  // bug 160042.
-  bool isChrome;
-  nsresult rv = origin->SchemeIs("chrome", &isChrome);
-  if (NS_SUCCEEDED(rv) && !isChrome) {
-    rv = origin->GetAsciiHostPort(hostPort);
-    // Some implementations return an empty string, treat it as no support
-    // for asciiHost by that implementation.
-    if (hostPort.IsEmpty()) {
-      rv = NS_ERROR_FAILURE;
-    }
-  }
-
-  // We want the invariant that prinA.origin == prinB.origin i.f.f.
-  // prinA.equals(prinB). However, this requires that we impose certain constraints
-  // on the behavior and origin semantics of principals, and in particular, forbid
-  // creating origin strings for principals whose equality constraints are not
-  // expressible as strings (i.e. object equality). Moreover, we want to forbid URIs
-  // containing the magic "^" we use as a separating character for origin
-  // attributes.
-  //
-  // These constraints can generally be achieved by restricting .origin to
-  // nsIStandardURL-based URIs, but there are a few other URI schemes that we need
-  // to handle.
-  bool isBehaved;
-  if ((NS_SUCCEEDED(origin->SchemeIs("about", &isBehaved)) && isBehaved) ||
-      (NS_SUCCEEDED(origin->SchemeIs("moz-safe-about", &isBehaved)) && isBehaved) ||
-      (NS_SUCCEEDED(origin->SchemeIs("indexeddb", &isBehaved)) && isBehaved)) {
-    rv = origin->GetAsciiSpec(aOrigin);
-    NS_ENSURE_SUCCESS(rv, rv);
-    // These URIs could technically contain a '^', but they never should.
-    if (NS_WARN_IF(aOrigin.FindChar('^', 0) != -1)) {
-      aOrigin.Truncate();
-      return NS_ERROR_FAILURE;
-    }
-    return NS_OK;
-  }
-
-  if (NS_SUCCEEDED(rv) && !isChrome) {
-    rv = origin->GetScheme(aOrigin);
-    NS_ENSURE_SUCCESS(rv, rv);
-    aOrigin.AppendLiteral("://");
-    aOrigin.Append(hostPort);
-    return NS_OK;
-  }
-
-  // This URL can be a blobURL. In this case, we should use the 'parent'
-  // principal instead.
-  nsCOMPtr<nsIURIWithPrincipal> uriWithPrincipal = do_QueryInterface(origin);
-  if (uriWithPrincipal) {
-    nsCOMPtr<nsIPrincipal> uriPrincipal;
-    rv = uriWithPrincipal->GetPrincipal(getter_AddRefs(uriPrincipal));
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    if (uriPrincipal) {
-      return uriPrincipal->GetOriginNoSuffix(aOrigin);
-    }
-  }
-
-  // If we reached this branch, we can only create an origin if we have a
-  // nsIStandardURL.  So, we query to a nsIStandardURL, and fail if we aren't
-  // an instance of an nsIStandardURL nsIStandardURLs have the good property
-  // of escaping the '^' character in their specs, which means that we can be
-  // sure that the caret character (which is reserved for delimiting the end
-  // of the spec, and the beginning of the origin attributes) is not present
-  // in the origin string
-  nsCOMPtr<nsIStandardURL> standardURL = do_QueryInterface(origin);
-  NS_ENSURE_TRUE(standardURL, NS_ERROR_FAILURE);
-
-  rv = origin->GetAsciiSpec(aOrigin);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  // The origin, when taken from the spec, should not contain the ref part of
-  // the URL.
-
-  int32_t pos = aOrigin.FindChar('?');
-  int32_t hashPos = aOrigin.FindChar('#');
-
-  if (hashPos != kNotFound && (pos == kNotFound || hashPos < pos)) {
-    pos = hashPos;
-  }
-
-  if (pos != kNotFound) {
-    aOrigin.Truncate(pos);
-  }
-
-  return NS_OK;
-}
-
-bool
-nsPrincipal::SubsumesInternal(nsIPrincipal* aOther,
-                              BasePrincipal::DocumentDomainConsideration aConsideration)
-{
-  MOZ_ASSERT(aOther);
-
-  // For nsPrincipal, Subsumes is equivalent to Equals.
-  if (aOther == this) {
-    return true;
-  }
-
-  // If either the subject or the object has changed its principal by
-  // explicitly setting document.domain then the other must also have
-  // done so in order to be considered the same origin. This prevents
-  // DNS spoofing based on document.domain (154930)
-  nsresult rv;
-  if (aConsideration == ConsiderDocumentDomain) {
-    // Get .domain on each principal.
-    nsCOMPtr<nsIURI> thisDomain, otherDomain;
-    GetDomain(getter_AddRefs(thisDomain));
-    aOther->GetDomain(getter_AddRefs(otherDomain));
-
-    // If either has .domain set, we have equality i.f.f. the domains match.
-    // Otherwise, we fall through to the non-document-domain-considering case.
-    if (thisDomain || otherDomain) {
-      return nsScriptSecurityManager::SecurityCompareURIs(thisDomain, otherDomain);
-    }
-  }
-
-  nsCOMPtr<nsIURI> otherURI;
-  rv = aOther->GetURI(getter_AddRefs(otherURI));
-  NS_ENSURE_SUCCESS(rv, false);
-
-  // Compare codebases.
-  return nsScriptSecurityManager::SecurityCompareURIs(mCodebase, otherURI);
-}
-
-NS_IMETHODIMP
-nsPrincipal::GetURI(nsIURI** aURI)
-{
-  if (mCodebaseImmutable) {
-    NS_ADDREF(*aURI = mCodebase);
-    return NS_OK;
-  }
-
-  if (!mCodebase) {
-    *aURI = nullptr;
-    return NS_OK;
-  }
-
-  return NS_EnsureSafeToReturn(mCodebase, aURI);
-}
-
-bool
-nsPrincipal::MayLoadInternal(nsIURI* aURI)
-{
-  // See if aURI is something like a Blob URI that is actually associated with
-  // a principal.
-  nsCOMPtr<nsIURIWithPrincipal> uriWithPrin = do_QueryInterface(aURI);
-  nsCOMPtr<nsIPrincipal> uriPrin;
-  if (uriWithPrin) {
-    uriWithPrin->GetPrincipal(getter_AddRefs(uriPrin));
-  }
-  if (uriPrin) {
-    return nsIPrincipal::Subsumes(uriPrin);
-  }
-
-  // If this principal is associated with an addon, check whether that addon
-  // has been given permission to load from this domain.
-  if (AddonAllowsLoad(aURI)) {
-    return true;
-  }
-
-  if (nsScriptSecurityManager::SecurityCompareURIs(mCodebase, aURI)) {
-    return true;
-  }
-
-  // If strict file origin policy is in effect, local files will always fail
-  // SecurityCompareURIs unless they are identical. Explicitly check file origin
-  // policy, in that case.
-  if (nsScriptSecurityManager::GetStrictFileOriginPolicy() &&
-      NS_URIIsLocalFile(aURI) &&
-      NS_RelaxStrictFileOriginPolicy(aURI, mCodebase)) {
-    return true;
-  }
-
-  return false;
-}
-
-void
-nsPrincipal::SetURI(nsIURI* aURI)
-{
-  mCodebase = NS_TryToMakeImmutable(aURI);
-  mCodebaseImmutable = URIIsImmutable(mCodebase);
-}
-
-NS_IMETHODIMP
-nsPrincipal::GetHashValue(uint32_t* aValue)
-{
-  NS_PRECONDITION(mCodebase, "Need a codebase");
-
-  *aValue = nsScriptSecurityManager::HashPrincipalByOrigin(this);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsPrincipal::GetDomain(nsIURI** aDomain)
-{
-  if (!mDomain) {
-    *aDomain = nullptr;
-    return NS_OK;
-  }
-
-  if (mDomainImmutable) {
-    NS_ADDREF(*aDomain = mDomain);
-    return NS_OK;
-  }
-
-  return NS_EnsureSafeToReturn(mDomain, aDomain);
-}
-
-NS_IMETHODIMP
-nsPrincipal::SetDomain(nsIURI* aDomain)
-{
-  mDomain = NS_TryToMakeImmutable(aDomain);
-  mDomainImmutable = URIIsImmutable(mDomain);
-
-  // Recompute all wrappers between compartments using this principal and other
-  // non-chrome compartments.
-  AutoSafeJSContext cx;
-  JSPrincipals *principals = nsJSPrincipals::get(static_cast<nsIPrincipal*>(this));
-  bool success = js::RecomputeWrappers(cx, js::ContentCompartmentsOnly(),
-                                       js::CompartmentsWithPrincipals(principals));
-  NS_ENSURE_TRUE(success, NS_ERROR_FAILURE);
-  success = js::RecomputeWrappers(cx, js::CompartmentsWithPrincipals(principals),
-                                  js::ContentCompartmentsOnly());
-  NS_ENSURE_TRUE(success, NS_ERROR_FAILURE);
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsPrincipal::GetBaseDomain(nsACString& aBaseDomain)
-{
-  // For a file URI, we return the file path.
-  if (NS_URIIsLocalFile(mCodebase)) {
-    nsCOMPtr<nsIURL> url = do_QueryInterface(mCodebase);
-
-    if (url) {
-      return url->GetFilePath(aBaseDomain);
-    }
-  }
-
-  bool hasNoRelativeFlag;
-  nsresult rv = NS_URIChainHasFlags(mCodebase,
-                                    nsIProtocolHandler::URI_NORELATIVE,
-                                    &hasNoRelativeFlag);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  if (hasNoRelativeFlag) {
-    return mCodebase->GetSpec(aBaseDomain);
-  }
-
-  // For everything else, we ask the TLD service via
-  // the ThirdPartyUtil.
-  nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
-    do_GetService(THIRDPARTYUTIL_CONTRACTID);
-  if (thirdPartyUtil) {
-    return thirdPartyUtil->GetBaseDomain(mCodebase, aBaseDomain);
-  }
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsPrincipal::Read(nsIObjectInputStream* aStream)
-{
-  nsCOMPtr<nsISupports> supports;
-  nsCOMPtr<nsIURI> codebase;
-  nsresult rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-
-  codebase = do_QueryInterface(supports);
-
-  nsCOMPtr<nsIURI> domain;
-  rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-
-  domain = do_QueryInterface(supports);
-
-  nsAutoCString suffix;
-  rv = aStream->ReadCString(suffix);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  OriginAttributes attrs;
-  bool ok = attrs.PopulateFromSuffix(suffix);
-  NS_ENSURE_TRUE(ok, NS_ERROR_FAILURE);
-
-  rv = NS_ReadOptionalObject(aStream, true, getter_AddRefs(supports));
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = Init(codebase, attrs);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  mCSP = do_QueryInterface(supports, &rv);
-  // make sure setRequestContext is called after Init(),
-  // to make sure  the principals URI been initalized.
-  if (mCSP) {
-    mCSP->SetRequestContext(nullptr, this);
-  }
-
-  SetDomain(domain);
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsPrincipal::Write(nsIObjectOutputStream* aStream)
-{
-  NS_ENSURE_STATE(mCodebase);
-  nsresult rv = NS_WriteOptionalCompoundObject(aStream, mCodebase, NS_GET_IID(nsIURI),
-                                               true);
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-
-  rv = NS_WriteOptionalCompoundObject(aStream, mDomain, NS_GET_IID(nsIURI),
-                                      true);
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-
-  nsAutoCString suffix;
-  OriginAttributesRef().CreateSuffix(suffix);
-
-  rv = aStream->WriteStringZ(suffix.get());
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = NS_WriteOptionalCompoundObject(aStream, mCSP,
-                                      NS_GET_IID(nsIContentSecurityPolicy),
-                                      true);
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
-
-  // mCodebaseImmutable and mDomainImmutable will be recomputed based
-  // on the deserialized URIs in Read().
-
-  return NS_OK;
-}
-
-/************************************************************************************************************************/
-
 NS_IMPL_CLASSINFO(nsExpandedPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
                   NS_EXPANDEDPRINCIPAL_CID)
 NS_IMPL_QUERY_INTERFACE_CI(nsExpandedPrincipal,
                            nsIPrincipal,
                            nsIExpandedPrincipal)
 NS_IMPL_CI_INTERFACE_GETTER(nsExpandedPrincipal,
                              nsIPrincipal,
                              nsIExpandedPrincipal)

copy from caps/nsPrincipal.h
copy to caps/nsExpandedPrincipal.h
--- a/caps/nsPrincipal.h
+++ b/caps/nsExpandedPrincipal.h
@@ -1,69 +1,24 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 
-#ifndef nsPrincipal_h__
-#define nsPrincipal_h__
+#ifndef nsExpandedPrincipal_h
+#define nsExpandedPrincipal_h
 
 #include "nsCOMPtr.h"
 #include "nsJSPrincipals.h"
 #include "nsTArray.h"
-#include "nsIContentSecurityPolicy.h"
-#include "nsIProtocolHandler.h"
 #include "nsNetUtil.h"
-#include "nsScriptSecurityManager.h"
 #include "mozilla/BasePrincipal.h"
 
-class nsPrincipal final : public mozilla::BasePrincipal
-{
-public:
-  NS_DECL_NSISERIALIZABLE
-  NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
-  NS_IMETHOD GetHashValue(uint32_t* aHashValue) override;
-  NS_IMETHOD GetURI(nsIURI** aURI) override;
-  NS_IMETHOD GetDomain(nsIURI** aDomain) override;
-  NS_IMETHOD SetDomain(nsIURI* aDomain) override;
-  NS_IMETHOD GetBaseDomain(nsACString& aBaseDomain) override;
-  bool IsCodebasePrincipal() const override { return true; }
-  nsresult GetOriginInternal(nsACString& aOrigin) override;
-
-  nsPrincipal();
-
-  // Init() must be called before the principal is in a usable state.
-  nsresult Init(nsIURI* aCodebase,
-                const mozilla::OriginAttributes& aOriginAttributes);
-
-  virtual nsresult GetScriptLocation(nsACString& aStr) override;
-  void SetURI(nsIURI* aURI);
-
-  /**
-   * Called at startup to setup static data, e.g. about:config pref-observers.
-   */
-  static void InitializeStatics();
-
-  PrincipalKind Kind() override { return eCodebasePrincipal; }
-
-  nsCOMPtr<nsIURI> mDomain;
-  nsCOMPtr<nsIURI> mCodebase;
-  // If mCodebaseImmutable is true, mCodebase is non-null and immutable
-  bool mCodebaseImmutable;
-  bool mDomainImmutable;
-  bool mInitialized;
-
-protected:
-  virtual ~nsPrincipal();
-
-  bool SubsumesInternal(nsIPrincipal* aOther, DocumentDomainConsideration aConsideration) override;
-  bool MayLoadInternal(nsIURI* aURI) override;
-};
-
-class nsExpandedPrincipal : public nsIExpandedPrincipal, public mozilla::BasePrincipal
+class nsExpandedPrincipal : public nsIExpandedPrincipal
+                          , public mozilla::BasePrincipal
 {
 public:
   nsExpandedPrincipal(nsTArray<nsCOMPtr<nsIPrincipal>> &aWhiteList,
                       const mozilla::OriginAttributes& aAttrs);
 
   NS_DECL_NSIEXPANDEDPRINCIPAL
   NS_DECL_NSISERIALIZABLE
   NS_IMETHOD_(MozExternalRefCountType) AddRef() override { return nsJSPrincipals::AddRef(); };
@@ -85,19 +40,14 @@ protected:
 
   bool SubsumesInternal(nsIPrincipal* aOther, DocumentDomainConsideration aConsideration) override;
   bool MayLoadInternal(nsIURI* aURI) override;
 
 private:
   nsTArray< nsCOMPtr<nsIPrincipal> > mPrincipals;
 };
 
-#define NS_PRINCIPAL_CONTRACTID "@mozilla.org/principal;1"
-#define NS_PRINCIPAL_CID \
-{ 0x653e0e4d, 0x3ee4, 0x45fa, \
-  { 0xb2, 0x72, 0x97, 0xc2, 0x0b, 0xc0, 0x1e, 0xb8 } }
-
 #define NS_EXPANDEDPRINCIPAL_CONTRACTID "@mozilla.org/expandedprincipal;1"
 #define NS_EXPANDEDPRINCIPAL_CID \
 { 0xe8ee88b0, 0x5571, 0x4086, \
   { 0xa4, 0x5b, 0x39, 0xa7, 0x16, 0x90, 0x6b, 0xdb } }
 
-#endif // nsPrincipal_h__
+#endif // nsExpandedPrincipal_h

--- a/caps/nsIPrincipal.idl
+++ b/caps/nsIPrincipal.idl
@@ -6,19 +6,39 @@
 /* Defines the abstract interface for a principal. */
 
 #include "nsISerializable.idl"
 
 %{C++
 struct JSPrincipals;
 #include "nsCOMPtr.h"
 #include "nsTArray.h"
+#include "mozilla/DebugOnly.h"
 namespace mozilla {
 class OriginAttributes;
 }
+
+/**
+ * Some methods have a fast path for the case when we're comparing a principal
+ * to itself. The situation may happen for example with about:blank documents.
+ */
+
+#define DECL_FAST_INLINE_HELPER(method_)                       \
+  inline bool method_(nsIPrincipal* aOther)                    \
+  {                                                            \
+    mozilla::DebugOnly<bool> val = false;                      \
+    MOZ_ASSERT_IF(this == aOther,                              \
+                  NS_SUCCEEDED(method_(aOther, &val)) && val); \
+                                                               \
+    bool retVal = false;                                       \
+    return                                                     \
+      this == aOther ||                                        \
+      (NS_SUCCEEDED(method_(aOther, &retVal)) && retVal);      \
+  }
+
 %}
 
 interface nsIURI;
 interface nsIContentSecurityPolicy;
 interface nsIDOMDocument;
 
 [ptr] native JSContext(JSContext);
 [ptr] native JSPrincipals(JSPrincipals);
@@ -36,25 +56,18 @@ interface nsIPrincipal : nsISerializable
     boolean equals(in nsIPrincipal other);
 
     /**
      * Like equals, but takes document.domain changes into account.
      */
     boolean equalsConsideringDomain(in nsIPrincipal other);
 
     %{C++
-    inline bool Equals(nsIPrincipal* aOther) {
-      bool equal = false;
-      return NS_SUCCEEDED(Equals(aOther, &equal)) && equal;
-    }
-
-    inline bool EqualsConsideringDomain(nsIPrincipal* aOther) {
-      bool equal = false;
-      return NS_SUCCEEDED(EqualsConsideringDomain(aOther, &equal)) && equal;
-    }
+      DECL_FAST_INLINE_HELPER(Equals)
+      DECL_FAST_INLINE_HELPER(EqualsConsideringDomain)
     %}
 
     /**
      * Returns a hash value for the principal.
      */
     [noscript] readonly attribute unsigned long hashValue;
 
     /**
@@ -96,30 +109,20 @@ interface nsIPrincipal : nsISerializable
 
     /**
      * Same as the subsumesConsideringDomain(), but ignores the first party
      * domain in its originAttributes.
      */
     boolean subsumesConsideringDomainIgnoringFPD(in nsIPrincipal other);
 
     %{C++
-    inline bool Subsumes(nsIPrincipal* aOther) {
-      bool subsumes = false;
-      return NS_SUCCEEDED(Subsumes(aOther, &subsumes)) && subsumes;
-    }
-
-    inline bool SubsumesConsideringDomain(nsIPrincipal* aOther) {
-      bool subsumes = false;
-      return NS_SUCCEEDED(SubsumesConsideringDomain(aOther, &subsumes)) && subsumes;
-    }
-
-    inline bool SubsumesConsideringDomainIgnoringFPD(nsIPrincipal* aOther) {
-      bool subsumes = false;
-      return NS_SUCCEEDED(SubsumesConsideringDomainIgnoringFPD(aOther, &subsumes)) && subsumes;
-    }
+      DECL_FAST_INLINE_HELPER(Subsumes)
+      DECL_FAST_INLINE_HELPER(SubsumesConsideringDomain)
+      DECL_FAST_INLINE_HELPER(SubsumesConsideringDomainIgnoringFPD)
+#undef DECL_FAST_INLINE_HELPER
     %}
 
     /**
      * Checks whether this principal is allowed to load the network resource
      * located at the given URI under the same-origin policy. This means that
      * codebase principals are only allowed to load resources from the same
      * domain, the system principal is allowed to load anything, and null
      * principals can only load URIs where they are the principal. This is

--- a/caps/nsPrincipal.cpp
+++ b/caps/nsPrincipal.cpp
@@ -453,208 +453,8 @@ nsPrincipal::Write(nsIObjectOutputStream
     return rv;
   }
 
   // mCodebaseImmutable and mDomainImmutable will be recomputed based
   // on the deserialized URIs in Read().
 
   return NS_OK;
 }
-
-/************************************************************************************************************************/
-
-NS_IMPL_CLASSINFO(nsExpandedPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
-                  NS_EXPANDEDPRINCIPAL_CID)
-NS_IMPL_QUERY_INTERFACE_CI(nsExpandedPrincipal,
-                           nsIPrincipal,
-                           nsIExpandedPrincipal)
-NS_IMPL_CI_INTERFACE_GETTER(nsExpandedPrincipal,
-                             nsIPrincipal,
-                             nsIExpandedPrincipal)
-
-struct OriginComparator
-{
-  bool LessThan(nsIPrincipal* a, nsIPrincipal* b) const
-  {
-    nsAutoCString originA;
-    nsresult rv = a->GetOrigin(originA);
-    NS_ENSURE_SUCCESS(rv, false);
-    nsAutoCString originB;
-    rv = b->GetOrigin(originB);
-    NS_ENSURE_SUCCESS(rv, false);
-    return originA < originB;
-  }
-
-  bool Equals(nsIPrincipal* a, nsIPrincipal* b) const
-  {
-    nsAutoCString originA;
-    nsresult rv = a->GetOrigin(originA);
-    NS_ENSURE_SUCCESS(rv, false);
-    nsAutoCString originB;
-    rv = b->GetOrigin(originB);
-    NS_ENSURE_SUCCESS(rv, false);
-    return a == b;
-  }
-};
-
-nsExpandedPrincipal::nsExpandedPrincipal(nsTArray<nsCOMPtr<nsIPrincipal>> &aWhiteList,
-                                         const OriginAttributes& aAttrs)
-{
-  // We force the principals to be sorted by origin so that nsExpandedPrincipal
-  // origins can have a canonical form.
-  OriginComparator c;
-  for (size_t i = 0; i < aWhiteList.Length(); ++i) {
-    mPrincipals.InsertElementSorted(aWhiteList[i], c);
-  }
-  mOriginAttributes = aAttrs;
-}
-
-nsExpandedPrincipal::~nsExpandedPrincipal()
-{ }
-
-NS_IMETHODIMP
-nsExpandedPrincipal::GetDomain(nsIURI** aDomain)
-{
-  *aDomain = nullptr;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::SetDomain(nsIURI* aDomain)
-{
-  return NS_OK;
-}
-
-nsresult
-nsExpandedPrincipal::GetOriginInternal(nsACString& aOrigin)
-{
-  aOrigin.AssignLiteral("[Expanded Principal [");
-  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
-    if (i != 0) {
-      aOrigin.AppendLiteral(", ");
-    }
-
-    nsAutoCString subOrigin;
-    nsresult rv = mPrincipals.ElementAt(i)->GetOrigin(subOrigin);
-    NS_ENSURE_SUCCESS(rv, rv);
-    aOrigin.Append(subOrigin);
-  }
-
-  aOrigin.Append("]]");
-  return NS_OK;
-}
-
-bool
-nsExpandedPrincipal::SubsumesInternal(nsIPrincipal* aOther,
-                                      BasePrincipal::DocumentDomainConsideration aConsideration)
-{
-  // If aOther is an ExpandedPrincipal too, we break it down into its component
-  // nsIPrincipals, and check subsumes on each one.
-  nsCOMPtr<nsIExpandedPrincipal> expanded = do_QueryInterface(aOther);
-  if (expanded) {
-    nsTArray< nsCOMPtr<nsIPrincipal> >* otherList;
-    expanded->GetWhiteList(&otherList);
-    for (uint32_t i = 0; i < otherList->Length(); ++i){
-      // Use SubsumesInternal rather than Subsumes here, since OriginAttribute
-      // checks are only done between non-expanded sub-principals, and we don't
-      // need to incur the extra virtual call overhead.
-      if (!SubsumesInternal((*otherList)[i], aConsideration)) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  // We're dealing with a regular principal. One of our principals must subsume
-  // it.
-  for (uint32_t i = 0; i < mPrincipals.Length(); ++i) {
-    if (Cast(mPrincipals[i])->Subsumes(aOther, aConsideration)) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
-bool
-nsExpandedPrincipal::MayLoadInternal(nsIURI* uri)
-{
-  for (uint32_t i = 0; i < mPrincipals.Length(); ++i){
-    if (BasePrincipal::Cast(mPrincipals[i])->MayLoadInternal(uri)) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::GetHashValue(uint32_t* result)
-{
-  MOZ_CRASH("extended principal should never be used as key in a hash map");
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::GetURI(nsIURI** aURI)
-{
-  *aURI = nullptr;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::GetWhiteList(nsTArray<nsCOMPtr<nsIPrincipal> >** aWhiteList)
-{
-  *aWhiteList = &mPrincipals;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::GetBaseDomain(nsACString& aBaseDomain)
-{
-  return NS_ERROR_NOT_AVAILABLE;
-}
-
-bool
-nsExpandedPrincipal::AddonHasPermission(const nsAString& aPerm)
-{
-  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
-    if (BasePrincipal::Cast(mPrincipals[i])->AddonHasPermission(aPerm)) {
-      return true;
-    }
-  }
-  return false;
-}
-
-nsresult
-nsExpandedPrincipal::GetScriptLocation(nsACString& aStr)
-{
-  aStr.Assign("[Expanded Principal [");
-  for (size_t i = 0; i < mPrincipals.Length(); ++i) {
-    if (i != 0) {
-      aStr.AppendLiteral(", ");
-    }
-
-    nsAutoCString spec;
-    nsresult rv =
-      nsJSPrincipals::get(mPrincipals.ElementAt(i))->GetScriptLocation(spec);
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    aStr.Append(spec);
-  }
-  aStr.Append("]]");
-  return NS_OK;
-}
-
-//////////////////////////////////////////
-// Methods implementing nsISerializable //
-//////////////////////////////////////////
-
-NS_IMETHODIMP
-nsExpandedPrincipal::Read(nsIObjectInputStream* aStream)
-{
-  return NS_ERROR_NOT_IMPLEMENTED;
-}
-
-NS_IMETHODIMP
-nsExpandedPrincipal::Write(nsIObjectOutputStream* aStream)
-{
-  return NS_ERROR_NOT_IMPLEMENTED;
-}