diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index cf087c44550..01331f058ec 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -6133,103 +6133,114 @@ function charsetLoadListener(event) {
   }
 }
 
-/* Begin Page Style Functions */
-function getAllStyleSheets(frameset) {
-  var styleSheetsArray = Array.slice(frameset.document.styleSheets);
-  for (let i = 0; i < frameset.frames.length; i++) {
-    let frameSheets = getAllStyleSheets(frameset.frames[i]);
-    styleSheetsArray = styleSheetsArray.concat(frameSheets);
-  }
-  return styleSheetsArray;
-}
 
-function stylesheetFillPopup(menuPopup) {
-  var noStyle = menuPopup.firstChild;
-  var persistentOnly = noStyle.nextSibling;
-  var sep = persistentOnly.nextSibling;
-  while (sep.nextSibling)
-    menuPopup.removeChild(sep.nextSibling);
+var gPageStyleMenu = {
 
-  var styleSheets = getAllStyleSheets(window.content);
-  var currentStyleSheets = {};
-  var styleDisabled = getMarkupDocumentViewer().authorStyleDisabled;
-  var haveAltSheets = false;
-  var altStyleSelected = false;
+  getAllStyleSheets: function (frameset) {
+    var styleSheetsArray = Array.slice(frameset.document.styleSheets);
+    for (let i = 0; i < frameset.frames.length; i++) {
+      let frameSheets = this.getAllStyleSheets(frameset.frames[i]);
+      styleSheetsArray = styleSheetsArray.concat(frameSheets);
+    }
+    return styleSheetsArray;
+  },
 
-  for (let i = 0; i < styleSheets.length; ++i) {
-    let currentStyleSheet = styleSheets[i];
+  stylesheetFillPopup: function (menuPopup) {
+    var noStyle = menuPopup.firstChild;
+    var persistentOnly = noStyle.nextSibling;
+    var sep = persistentOnly.nextSibling;
+    while (sep.nextSibling)
+      menuPopup.removeChild(sep.nextSibling);
 
-    if (!currentStyleSheet.title)
-      continue;
+    var styleSheets = this.getAllStyleSheets(window.content);
+    var currentStyleSheets = {};
+    var styleDisabled = getMarkupDocumentViewer().authorStyleDisabled;
+    var haveAltSheets = false;
+    var altStyleSelected = false;
 
-    // Skip any stylesheets whose media attribute doesn't match.
-    if (currentStyleSheet.media.length > 0) {
-      let mediaQueryList = currentStyleSheet.media.mediaText;
-      if (!window.content.matchMedia(mediaQueryList).matches)
+    for (let i = 0; i < styleSheets.length; ++i) {
+      let currentStyleSheet = styleSheets[i];
+
+      if (!currentStyleSheet.title)
         continue;
+
+      // Skip any stylesheets whose media attribute doesn't match.
+      if (currentStyleSheet.media.length > 0) {
+        let mediaQueryList = currentStyleSheet.media.mediaText;
+        if (!window.content.matchMedia(mediaQueryList).matches)
+          continue;
+      }
+
+      if (!currentStyleSheet.disabled)
+        altStyleSelected = true;
+
+      haveAltSheets = true;
+
+      let lastWithSameTitle = null;
+      if (currentStyleSheet.title in currentStyleSheets)
+        lastWithSameTitle = currentStyleSheets[currentStyleSheet.title];
+
+      if (!lastWithSameTitle) {
+        let menuItem = document.createElement("menuitem");
+        menuItem.setAttribute("type", "radio");
+        menuItem.setAttribute("label", currentStyleSheet.title);
+        menuItem.setAttribute("data", currentStyleSheet.title);
+        menuItem.setAttribute("checked", !currentStyleSheet.disabled && !styleDisabled);
+        menuPopup.appendChild(menuItem);
+        currentStyleSheets[currentStyleSheet.title] = menuItem;
+      } else if (currentStyleSheet.disabled) {
+        lastWithSameTitle.removeAttribute("checked");
+      }
     }
 
-    if (!currentStyleSheet.disabled)
-      altStyleSelected = true;
+    noStyle.setAttribute("checked", styleDisabled);
+    persistentOnly.setAttribute("checked", !altStyleSelected && !styleDisabled);
+    persistentOnly.hidden = (window.content.document.preferredStyleSheetSet) ? haveAltSheets : false;
+    sep.hidden = (noStyle.hidden && persistentOnly.hidden) || !haveAltSheets;
+    return true;
+  },
 
-    haveAltSheets = true;
+  stylesheetInFrame: function (frame, title) {
+    return Array.some(frame.document.styleSheets,
+                      function (stylesheet) stylesheet.title == title);
+  },
 
-    let lastWithSameTitle = null;
-    if (currentStyleSheet.title in currentStyleSheets)
-      lastWithSameTitle = currentStyleSheets[currentStyleSheet.title];
+  stylesheetSwitchFrame: function (frame, title) {
+    var docStyleSheets = frame.document.styleSheets;
 
-    if (!lastWithSameTitle) {
-      let menuItem = document.createElement("menuitem");
-      menuItem.setAttribute("type", "radio");
-      menuItem.setAttribute("label", currentStyleSheet.title);
-      menuItem.setAttribute("data", currentStyleSheet.title);
-      menuItem.setAttribute("checked", !currentStyleSheet.disabled && !styleDisabled);
-      menuPopup.appendChild(menuItem);
-      currentStyleSheets[currentStyleSheet.title] = menuItem;
-    } else if (currentStyleSheet.disabled) {
-      lastWithSameTitle.removeAttribute("checked");
+    for (let i = 0; i < docStyleSheets.length; ++i) {
+      let docStyleSheet = docStyleSheets[i];
+
+      if (title == "_nostyle")
+        docStyleSheet.disabled = true;
+      else if (docStyleSheet.title)
+        docStyleSheet.disabled = (docStyleSheet.title != title);
+      else if (docStyleSheet.disabled)
+        docStyleSheet.disabled = false;
     }
-  }
+  },
 
-  noStyle.setAttribute("checked", styleDisabled);
-  persistentOnly.setAttribute("checked", !altStyleSelected && !styleDisabled);
-  persistentOnly.hidden = (window.content.document.preferredStyleSheetSet) ? haveAltSheets : false;
-  sep.hidden = (noStyle.hidden && persistentOnly.hidden) || !haveAltSheets;
-  return true;
-}
+  stylesheetSwitchAll: function (frameset, title) {
+    if (!title || title == "_nostyle" || this.stylesheetInFrame(frameset, title))
+      this.stylesheetSwitchFrame(frameset, title);
 
-function stylesheetInFrame(frame, title) {
-  return Array.some(frame.document.styleSheets,
-                    function (stylesheet) stylesheet.title == title);
-}
+    for (let i = 0; i < frameset.frames.length; i++)
+      this.stylesheetSwitchAll(frameset.frames[i], title);
+  },
 
-function stylesheetSwitchFrame(frame, title) {
-  var docStyleSheets = frame.document.styleSheets;
+  setStyleDisabled: function (disabled) {
+    getMarkupDocumentViewer().authorStyleDisabled = disabled;
+  },
+};
 
-  for (let i = 0; i < docStyleSheets.length; ++i) {
-    let docStyleSheet = docStyleSheets[i];
+/* Legacy global page-style functions */
+var getAllStyleSheets     = gPageStyleMenu.getAllStyleSheets;
+var stylesheetFillPopup   = gPageStyleMenu.stylesheetFillPopup;
+var stylesheetInFrame     = gPageStyleMenu.stylesheetInFrame;
+var stylesheetSwitchFrame = gPageStyleMenu.stylesheetSwitchFrame;
+var stylesheetSwitchAll   = gPageStyleMenu.stylesheetSwitchAll;
+var setStyleDisabled      = gPageStyleMenu.setStyleDisabled;
 
-    if (title == "_nostyle")
-      docStyleSheet.disabled = true;
-    else if (docStyleSheet.title)
-      docStyleSheet.disabled = (docStyleSheet.title != title);
-    else if (docStyleSheet.disabled)
-      docStyleSheet.disabled = false;
-  }
-}
-
-function stylesheetSwitchAll(frameset, title) {
-  if (!title || title == "_nostyle" || stylesheetInFrame(frameset, title))
-    stylesheetSwitchFrame(frameset, title);
-
-  for (let i = 0; i < frameset.frames.length; i++)
-    stylesheetSwitchAll(frameset.frames[i], title);
-}
-
-function setStyleDisabled(disabled) {
-  getMarkupDocumentViewer().authorStyleDisabled = disabled;
-}
-/* End of the Page Style functions */
 
 var BrowserOffline = {
   _inited: false,