Fix some initialization order issues.

common/content/commandline.js

@@ -1390,7 +1390,7 @@ var CommandLine = Module("commandline", {
                 subCommand: 0
             });
     },
-    modes: function () {
+    modes: function initModes() {
         modes.addMode("COMMAND_LINE", {
             char: "c",
             description: "Active when the command line is focused",

common/content/hints.js

@@ -1115,7 +1115,8 @@ var Hints = Module("hints", {
     Mode: Struct("HintMode", "name", "prompt", "action", "tags", "filter")
             .localize("prompt")
 }, {
-    modes: function () {
+    modes: function initModes() {
+        initModes.require("commandline");
         modes.addMode("HINTS", {
             extended: true,
             description: "Active when selecting elements in QuickHint or ExtendedHint mode",

common/content/modes.js

@@ -426,6 +426,10 @@ var Modes = Module("modes", {
 }, {
     Mode: Class("Mode", {
         init: function init(name, options, params) {
+            if (options.bases)
+                util.assert(options.bases.every(function (m) m instanceof this, this.constructor),
+                            "Invalid bases", true);
+
             update(this, {
                 id: 1 << Modes.Mode._id++,
                 name: name,

common/modules/io.jsm

@@ -996,7 +996,8 @@ unlet s:cpo_save
             }]);
 
     },
-    modes: function (dactyl, modules, window) {
+    modes: function initModes(dactyl, modules, window) {
+        initModes.require("commandline");
         const { modes } = modules;
 
         modes.addMode("FILE_INPUT", {

common/modules/javascript.jsm

@@ -700,6 +700,7 @@ var JavaScript = Module("javascript", {
         });
     },
     modes: function initModes(dactyl, modules, window) {
+        initModes.require("commandline");
         const { modes } = modules;
 
         modes.addMode("REPL", {

common/modules/util.jsm

@@ -931,7 +931,10 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
                 let docShells = window.docShell.getDocShellEnumerator(Ci.nsIDocShellTreeItem[type],
                                                                       Ci.nsIDocShell.ENUMERATE_FORWARDS);
                 while (docShells.hasMoreElements())
-                    yield docShells.getNext().QueryInterface(Ci.nsIDocShell).contentViewer.DOMDocument;
+                    let (viewer = docShells.getNext().QueryInterface(Ci.nsIDocShell).contentViewer) {
+                        if (viewer)
+                            yield viewer.DOMDocument;
+                    }
             }
         }
     },