Bug 1026093 - Don't allow the user to open an e10s window in safe mode r=mconley

browser/base/content/browser.js

@@ -7419,6 +7419,11 @@ let gRemoteTabsUI = {
       return;
     }
 
+    if (Services.appinfo.inSafeMode) {
+      // e10s isn't supported in safe mode, so don't show the menu items for it
+      return;
+    }
+
     let newRemoteWindow = document.getElementById("menu_newRemoteWindow");
     let newNonRemoteWindow = document.getElementById("menu_newNonRemoteWindow");
     let autostart = Services.appinfo.browserTabsRemoteAutostart;

browser/components/customizableui/CustomizableWidgets.jsm

@@ -1076,6 +1076,7 @@ CustomizableWidgets.push({
   id: "e10s-button",
   label: buttonLabel,
   tooltiptext: buttonLabel,
+  disabled: Services.appinfo.inSafeMode,
   defaultArea: CustomizableUI.AREA_PANEL,
   onCommand: getCommandFunction(openRemote),
 });