Bug 1288107 - Remove All Devices option in Send Tab to Device menu when we only have 1 other device. r=markh

MozReview-Commit-ID: FaqjglxeMCh

--HG--
extra : transplant_source : w%9F%CF%C1%C4a%8C%1E%9C%B1%5B%98rl%40%C4.Ne%B2

browser/base/content/browser-fxaccounts.js

@@ -407,10 +407,12 @@ var gFxAccounts = {
     }
 
     // "All devices" menu item
-    const separator = document.createElement("menuseparator");
-    fragment.appendChild(separator);
-    const allDevicesLabel = this.strings.GetStringFromName("sendTabToAllDevices.menuitem");
-    addTargetDevice("", allDevicesLabel);
+    if (clients.length > 1) {
+      const separator = document.createElement("menuseparator");
+      fragment.appendChild(separator);
+      const allDevicesLabel = this.strings.GetStringFromName("sendTabToAllDevices.menuitem");
+      addTargetDevice("", allDevicesLabel);
+    }
 
     devicesPopup.appendChild(fragment);
   },