--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -575,46 +575,16 @@ const gStoragePressureObserver = {
       });
     }
 
     notificationBox.appendNotification(
       msg, NOTIFICATION_VALUE, null, notificationBox.PRIORITY_WARNING_HIGH, buttons, null);
   }
 };
 
-/**
- * Given a starting docshell and a URI to look up, find the docshell the URI
- * is loaded in.
- * @param   aDocument
- *          A document to find instead of using just a URI - this is more specific.
- * @param   aDocShell
- *          The doc shell to start at
- * @param   aSoughtURI
- *          The URI that we're looking for
- * @returns The doc shell that the sought URI is loaded in. Can be in
- *          subframes.
- */
-function findChildShell(aDocument, aDocShell, aSoughtURI) {
-  aDocShell.QueryInterface(Ci.nsIWebNavigation);
-  aDocShell.QueryInterface(Ci.nsIInterfaceRequestor);
-  var doc = aDocShell.getInterface(Ci.nsIDOMDocument);
-  if ((aDocument && doc == aDocument) ||
-      (aSoughtURI && aSoughtURI.spec == aDocShell.currentURI.spec))
-    return aDocShell;
-
-  var node = aDocShell.QueryInterface(Ci.nsIDocShellTreeItem);
-  for (var i = 0; i < node.childCount; ++i) {
-    var docShell = node.getChildAt(i);
-    docShell = findChildShell(aDocument, docShell, aSoughtURI);
-    if (docShell)
-      return docShell;
-  }
-  return null;
-}
-
 var gPopupBlockerObserver = {
   handleEvent(aEvent) {
     if (aEvent.originalTarget != gBrowser.selectedBrowser)
       return;
 
     gIdentityHandler.refreshIdentityBlock();
 
     if (!gBrowser.selectedBrowser.blockedPopups ||

--- a/browser/base/content/tabbrowser.js
+++ b/browser/base/content/tabbrowser.js
@@ -365,20 +365,16 @@ window._gBrowser = {
   get docShell() {
     return this.selectedBrowser.docShell;
   },
 
   get webNavigation() {
     return this.selectedBrowser.webNavigation;
   },
 
-  get webBrowserFind() {
-    return this.selectedBrowser.webBrowserFind;
-  },
-
   get webProgress() {
     return this.selectedBrowser.webProgress;
   },
 
   get contentWindow() {
     return this.selectedBrowser.contentWindow;
   },
 

--- a/toolkit/content/widgets/browser.xml
+++ b/toolkit/content/widgets/browser.xml
@@ -161,20 +161,16 @@
       <property name="documentURI"
                 onget="return this.contentDocument.documentURIObject;"
                 readonly="true"/>
 
       <property name="documentContentType"
                 onget="return this.contentDocument ? this.contentDocument.contentType : null;"
                 readonly="true"/>
 
-      <property name="preferences"
-                onget="return this.mPrefs.QueryInterface(Components.interfaces.nsIPrefService);"
-                readonly="true"/>
-
       <!--
         Weak reference to an optional frame loader that can be used to influence
         process selection for this browser.
         See nsIBrowser.sameProcessAsFrameLoader.
       -->
       <field name="_sameProcessAsFrameLoader">null</field>
       <property name="sameProcessAsFrameLoader">
         <getter><![CDATA[
@@ -487,56 +483,34 @@
       </property>
 
       <property name="showWindowResizer"
                 onset="if (val) this.setAttribute('showresizer', 'true');
                        else this.removeAttribute('showresizer');
                        return val;"
                 onget="return this.getAttribute('showresizer') == 'true';"/>
 
-      <property name="manifestURI"
-                readonly="true">
-        <getter><![CDATA[
-          return this.contentDocument.documentElement &&
-                 this.contentDocument.documentElement.getAttribute("manifest");
-        ]]></getter>
-      </property>
-
       <property name="fullZoom">
         <getter><![CDATA[
           return this.markupDocumentViewer.fullZoom;
         ]]></getter>
         <setter><![CDATA[
           this.markupDocumentViewer.fullZoom = val;
         ]]></setter>
       </property>
 
-      <property name="deviceFullZoom"
-                readonly="true">
-        <getter><![CDATA[
-          return this.markupDocumentViewer.deviceFullZoom;
-        ]]></getter>
-      </property>
-
       <property name="textZoom">
         <getter><![CDATA[
           return this.markupDocumentViewer.textZoom;
         ]]></getter>
         <setter><![CDATA[
           this.markupDocumentViewer.textZoom = val;
         ]]></setter>
       </property>
 
-      <property name="effectiveTextZoom"
-                readonly="true">
-        <getter><![CDATA[
-          return this.markupDocumentViewer.effectiveTextZoom;
-        ]]></getter>
-      </property>
-
       <property name="isSyntheticDocument">
         <getter><![CDATA[
           return this.contentDocument.mozSyntheticDocument;
         ]]></getter>
       </property>
 
       <property name="hasContentOpener">
         <getter><![CDATA[
@@ -581,37 +555,16 @@
         <parameter name="aListener"/>
         <body>
           <![CDATA[
             this.webProgress.removeProgressListener(aListener);
          ]]>
         </body>
       </method>
 
-      <method name="findChildShell">
-        <parameter name="aDocShell"/>
-        <parameter name="aSoughtURI"/>
-        <body>
-          <![CDATA[
-            if (aDocShell.QueryInterface(Ci.nsIWebNavigation)
-                         .currentURI.spec == aSoughtURI.spec)
-              return aDocShell;
-            var node = aDocShell.QueryInterface(
-                                   Ci.nsIDocShellTreeItem);
-            for (var i = 0; i < node.childCount; ++i) {
-              var docShell = node.getChildAt(i);
-              docShell = this.findChildShell(docShell, aSoughtURI);
-              if (docShell)
-                return docShell;
-            }
-            return null;
-          ]]>
-        </body>
-      </method>
-
       <method name="onPageHide">
         <parameter name="aEvent"/>
         <body>
           <![CDATA[
             // Delete the feeds cache if we're hiding the topmost page
             // (as opposed to one of its iframes).
             if (this.feeds && aEvent.target == this.contentDocument)
               this.feeds = null;
@@ -894,24 +847,16 @@
                 onget="return this._userTypedValue;">
         <setter><![CDATA[
           this.urlbarChangeTracker.userTyped();
           this._userTypedValue = val;
           return val;
         ]]></setter>
       </property>
 
-      <field name="mFormFillAttached">
-        false
-      </field>
-
-      <field name="isShowingMessage">
-        false
-      </field>
-
       <field name="droppedLinkHandler">
         null
       </field>
 
       <field name="mIconURL">null</field>
 
       <!-- This is managed by the tabbrowser -->
       <field name="lastURI">null</field>

--- a/toolkit/content/widgets/remote-browser.xml
+++ b/toolkit/content/widgets/remote-browser.xml
@@ -271,21 +271,16 @@
           let {frameLoader} = this;
           if (frameLoader.tabParent) {
             return frameLoader.tabParent.hasLayers;
           }
           return false;
         ]]></getter>
       </property>
 
-      <field name="_manifestURI"/>
-      <property name="manifestURI"
-                onget="return this._manifestURI"
-                readonly="true"/>
-
       <field name="mDestroyed">false</field>
 
       <field name="_permitUnloadId">0</field>
 
       <method name="getInPermitUnload">
         <parameter name="aCallback"/>
         <body>
         <![CDATA[