new file mode 100644
--- /dev/null
+++ b/browser/base/content/contentSearchHandoffUI.js
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+function ContentSearchHandoffUIController() {
+  this._isPrivateWindow = false;
+  this._engineIcon = null;
+
+  window.addEventListener("ContentSearchService", this);
+  this._sendMsg("GetEngine");
+}
+
+ContentSearchHandoffUIController.prototype = {
+  handleEvent(event) {
+    let methodName = "_onMsg" + event.detail.type;
+    if (methodName in this) {
+      this[methodName](event.detail.data);
+    }
+  },
+
+  _onMsgEngine({ isPrivateWindow, engine }) {
+    this._isPrivateWindow = isPrivateWindow;
+    this._updateEngineIcon(engine);
+  },
+
+  _onMsgCurrentEngine(engine) {
+    if (!this._isPrivateWindow) {
+      this._updateEngineIcon(engine);
+    }
+  },
+
+  _onMsgCurrentPrivateEngine(engine) {
+    if (this._isPrivateWindow) {
+      this._updateEngineIcon(engine);
+    }
+  },
+
+  _updateEngineIcon(engine) {
+    if (this._engineIcon) {
+      URL.revokeObjectURL(this._engineIcon);
+    }
+
+    if (engine.iconData) {
+      this._engineIcon = this._getFaviconURIFromIconData(engine.iconData);
+    } else {
+      this._engineIcon = "chrome://mozapps/skin/places/defaultFavicon.svg";
+    }
+
+    document.body.style.setProperty(
+      "--newtab-search-icon",
+      "url(" + this._engineIcon + ")"
+    );
+  },
+
+  // If the favicon is an array buffer, convert it into a Blob URI.
+  // Otherwise just return the plain URI.
+  _getFaviconURIFromIconData(data) {
+    if (typeof data === "string") {
+      return data;
+    }
+
+    // If typeof(data) != "string", we assume it's an ArrayBuffer
+    let blob = new Blob([data]);
+    return URL.createObjectURL(blob);
+  },
+
+  _sendMsg(type, data = null) {
+    dispatchEvent(
+      new CustomEvent("ContentSearchClient", {
+        detail: {
+          type,
+          data,
+        },
+      })
+    );
+  },
+};

--- a/browser/base/jar.mn
+++ b/browser/base/jar.mn
@@ -89,16 +89,17 @@ browser.jar:
         content/browser/static-robot.png              (content/static-robot.png)
         content/browser/safeMode.css                  (content/safeMode.css)
         content/browser/safeMode.js                   (content/safeMode.js)
         content/browser/safeMode.xhtml                (content/safeMode.xhtml)
         content/browser/sanitize.xhtml                (content/sanitize.xhtml)
         content/browser/sanitizeDialog.js             (content/sanitizeDialog.js)
         content/browser/sanitizeDialog.css            (content/sanitizeDialog.css)
         content/browser/contentSearchUI.js            (content/contentSearchUI.js)
+        content/browser/contentSearchHandoffUI.js     (content/contentSearchHandoffUI.js)
         content/browser/contentSearchUI.css           (content/contentSearchUI.css)
         content/browser/tabbrowser.css                (content/tabbrowser.css)
         content/browser/tabbrowser.js                 (content/tabbrowser.js)
         content/browser/tabbrowser-tab.js             (content/tabbrowser-tab.js)
         content/browser/tabbrowser-tabs.js            (content/tabbrowser-tabs.js)
         content/browser/utilityOverlay.js             (content/utilityOverlay.js)
         content/browser/webext-panels.js              (content/webext-panels.js)
 *       content/browser/webext-panels.xhtml           (content/webext-panels.xhtml)

--- a/browser/components/newtab/bin/render-activity-stream-html.js
+++ b/browser/components/newtab/bin/render-activity-stream-html.js
@@ -23,16 +23,17 @@ const DEFAULT_OPTIONS = {
  *         {bool} options.debug         Should we use dev versions of JS libraries?
  *         {bool} options.noscripts     Should we include scripts in the prerendered files?
  * @return {str}         An HTML document as a string
  */
 function templateHTML(options) {
   const debugString = options.debug ? "-dev" : "";
   const scripts = [
     "chrome://browser/content/contentSearchUI.js",
+    "chrome://browser/content/contentSearchHandoffUI.js",
     "chrome://browser/content/contentTheme.js",
     `${options.baseUrl}vendor/react${debugString}.js`,
     `${options.baseUrl}vendor/react-dom${debugString}.js`,
     `${options.baseUrl}vendor/prop-types.js`,
     `${options.baseUrl}vendor/redux.js`,
     `${options.baseUrl}vendor/react-redux.js`,
     `${options.baseUrl}vendor/react-transition-group.js`,
     `${options.baseUrl}data/content/activity-stream.bundle.js`,

--- a/browser/components/newtab/content-src/components/Search/Search.jsx
+++ b/browser/components/newtab/content-src/components/Search/Search.jsx
@@ -1,28 +1,29 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* globals ContentSearchUIController */
+/* globals ContentSearchUIController, ContentSearchHandoffUIController */
 "use strict";
 
 import { actionCreators as ac, actionTypes as at } from "common/Actions.jsm";
 import { connect } from "react-redux";
 import { IS_NEWTAB } from "content-src/lib/constants";
 import React from "react";
 
 export class _Search extends React.PureComponent {
   constructor(props) {
     super(props);
     this.onSearchClick = this.onSearchClick.bind(this);
     this.onSearchHandoffClick = this.onSearchHandoffClick.bind(this);
     this.onSearchHandoffPaste = this.onSearchHandoffPaste.bind(this);
     this.onSearchHandoffDrop = this.onSearchHandoffDrop.bind(this);
     this.onInputMount = this.onInputMount.bind(this);
+    this.onInputMountHandoff = this.onInputMountHandoff.bind(this);
     this.onSearchHandoffButtonMount = this.onSearchHandoffButtonMount.bind(
       this
     );
   }
 
   handleEvent(event) {
     // Also track search events with our own telemetry
     if (event.detail.type === "Search") {
@@ -98,16 +99,24 @@ export class _Search extends React.PureC
       );
       addEventListener("ContentSearchClient", this);
     } else {
       window.gContentSearchController = null;
       removeEventListener("ContentSearchClient", this);
     }
   }
 
+  onInputMountHandoff(input) {
+    if (input) {
+      // The handoff UI controller helps usset the search icon and reacts to
+      // changes to default engine to keep everything in sync.
+      this._handoffSearchController = new ContentSearchHandoffUIController();
+    }
+  }
+
   onSearchHandoffButtonMount(button) {
     // Keep a reference to the button for use during "paste" event handling.
     this._searchHandoffButton = button;
   }
 
   /*
    * Do not change the ID on the input field, as legacy newtab code
    * specifically looks for the id 'newtab-search-text' on input fields
@@ -162,28 +171,20 @@ export class _Search extends React.PureC
               />
               <input
                 type="search"
                 className="fake-editable"
                 tabIndex="-1"
                 aria-hidden="true"
                 onDrop={this.onSearchHandoffDrop}
                 onPaste={this.onSearchHandoffPaste}
+                ref={this.onInputMountHandoff}
               />
               <div className="fake-caret" />
             </button>
-            {/*
-            This dummy and hidden input below is so we can load ContentSearchUIController.
-            Why? It sets --newtab-search-icon for us and it isn't trivial to port over.
-          */}
-            <input
-              type="search"
-              style={{ display: "none" }}
-              ref={this.onInputMount}
-            />
           </div>
         )}
       </div>
     );
   }
 }
 
 export const Search = connect()(_Search);

--- a/browser/components/newtab/data/content/activity-stream.bundle.js
+++ b/browser/components/newtab/data/content/activity-stream.bundle.js
@@ -10281,31 +10281,32 @@ const TopSites = Object(react_redux__WEB
 /* harmony import */ var react_redux__WEBPACK_IMPORTED_MODULE_1___default = /*#__PURE__*/__webpack_require__.n(react_redux__WEBPACK_IMPORTED_MODULE_1__);
 /* harmony import */ var content_src_lib_constants__WEBPACK_IMPORTED_MODULE_2__ = __webpack_require__(11);
 /* harmony import */ var react__WEBPACK_IMPORTED_MODULE_3__ = __webpack_require__(9);
 /* harmony import */ var react__WEBPACK_IMPORTED_MODULE_3___default = /*#__PURE__*/__webpack_require__.n(react__WEBPACK_IMPORTED_MODULE_3__);
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-/* globals ContentSearchUIController */
+/* globals ContentSearchUIController, ContentSearchHandoffUIController */
 
 
 
 
 
 
 class _Search extends react__WEBPACK_IMPORTED_MODULE_3___default.a.PureComponent {
   constructor(props) {
     super(props);
     this.onSearchClick = this.onSearchClick.bind(this);
     this.onSearchHandoffClick = this.onSearchHandoffClick.bind(this);
     this.onSearchHandoffPaste = this.onSearchHandoffPaste.bind(this);
     this.onSearchHandoffDrop = this.onSearchHandoffDrop.bind(this);
     this.onInputMount = this.onInputMount.bind(this);
+    this.onInputMountHandoff = this.onInputMountHandoff.bind(this);
     this.onSearchHandoffButtonMount = this.onSearchHandoffButtonMount.bind(this);
   }
 
   handleEvent(event) {
     // Also track search events with our own telemetry
     if (event.detail.type === "Search") {
       this.props.dispatch(common_Actions_jsm__WEBPACK_IMPORTED_MODULE_0__["actionCreators"].UserEvent({
         event: "SEARCH"
@@ -10385,16 +10386,24 @@ class _Search extends react__WEBPACK_IMP
       window.gContentSearchController = new ContentSearchUIController(input, input.parentNode, healthReportKey, searchSource);
       addEventListener("ContentSearchClient", this);
     } else {
       window.gContentSearchController = null;
       removeEventListener("ContentSearchClient", this);
     }
   }
 
+  onInputMountHandoff(input) {
+    if (input) {
+      // The handoff UI controller helps usset the search icon and reacts to
+      // changes to default engine to keep everything in sync.
+      this._handoffSearchController = new ContentSearchHandoffUIController();
+    }
+  }
+
   onSearchHandoffButtonMount(button) {
     // Keep a reference to the button for use during "paste" event handling.
     this._searchHandoffButton = button;
   }
   /*
    * Do not change the ID on the input field, as legacy newtab code
    * specifically looks for the id 'newtab-search-text' on input fields
    * in order to execute searches in various tests
@@ -10436,26 +10445,21 @@ class _Search extends react__WEBPACK_IMP
       className: "fake-textbox",
       "data-l10n-id": "newtab-search-box-search-the-web-text"
     }), react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("input", {
       type: "search",
       className: "fake-editable",
       tabIndex: "-1",
       "aria-hidden": "true",
       onDrop: this.onSearchHandoffDrop,
-      onPaste: this.onSearchHandoffPaste
+      onPaste: this.onSearchHandoffPaste,
+      ref: this.onInputMountHandoff
     }), react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("div", {
       className: "fake-caret"
-    })), react__WEBPACK_IMPORTED_MODULE_3___default.a.createElement("input", {
-      type: "search",
-      style: {
-        display: "none"
-      },
-      ref: this.onInputMount
-    })));
+    }))));
   }
 
 }
 const Search = Object(react_redux__WEBPACK_IMPORTED_MODULE_1__["connect"])()(_Search);
 
 /***/ }),
 /* 77 */
 /***/ (function(module, __webpack_exports__, __webpack_require__) {

--- a/browser/components/newtab/prerendered/activity-stream-debug.html
+++ b/browser/components/newtab/prerendered/activity-stream-debug.html
@@ -15,16 +15,17 @@
     <link rel="stylesheet" href="chrome://browser/content/contentSearchUI.css" />
     <link rel="stylesheet" href="resource://activity-stream/css/activity-stream.css" />
   </head>
   <body class="activity-stream">
     <div id="header-asrouter-container" role="presentation"></div>
     <div id="root"></div>
     <div id="footer-asrouter-container" role="presentation"></div>
     <script src="chrome://browser/content/contentSearchUI.js"></script>
+    <script src="chrome://browser/content/contentSearchHandoffUI.js"></script>
     <script src="chrome://browser/content/contentTheme.js"></script>
     <script src="resource://activity-stream/vendor/react-dev.js"></script>
     <script src="resource://activity-stream/vendor/react-dom-dev.js"></script>
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
     <script src="resource://activity-stream/vendor/react-transition-group.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>

--- a/browser/components/newtab/prerendered/activity-stream.html
+++ b/browser/components/newtab/prerendered/activity-stream.html
@@ -15,16 +15,17 @@
     <link rel="stylesheet" href="chrome://browser/content/contentSearchUI.css" />
     <link rel="stylesheet" href="resource://activity-stream/css/activity-stream.css" />
   </head>
   <body class="activity-stream">
     <div id="header-asrouter-container" role="presentation"></div>
     <div id="root"></div>
     <div id="footer-asrouter-container" role="presentation"></div>
     <script src="chrome://browser/content/contentSearchUI.js"></script>
+    <script src="chrome://browser/content/contentSearchHandoffUI.js"></script>
     <script src="chrome://browser/content/contentTheme.js"></script>
     <script src="resource://activity-stream/vendor/react.js"></script>
     <script src="resource://activity-stream/vendor/react-dom.js"></script>
     <script src="resource://activity-stream/vendor/prop-types.js"></script>
     <script src="resource://activity-stream/vendor/redux.js"></script>
     <script src="resource://activity-stream/vendor/react-redux.js"></script>
     <script src="resource://activity-stream/vendor/react-transition-group.js"></script>
     <script src="resource://activity-stream/data/content/activity-stream.bundle.js"></script>

--- a/browser/components/privatebrowsing/content/aboutPrivateBrowsing.js
+++ b/browser/components/privatebrowsing/content/aboutPrivateBrowsing.js
@@ -113,19 +113,10 @@ document.addEventListener("DOMContentLoa
     }
   });
   editable.addEventListener("paste", function(ev) {
     ev.preventDefault();
     handoffSearch(ev.clipboardData.getData("Text"));
   });
 
   // Load contentSearchUI so it sets the search engine icon for us.
-  // TODO: FIXME. We should eventually refector contentSearchUI to do only what
-  // we need and have it do the common search handoff work for
-  // about:newtab and about:privatebrowsing.
-  let input = document.getElementById("dummy-input");
-  new window.ContentSearchUIController(
-    input,
-    input.parentNode,
-    "aboutprivatebrowsing",
-    "aboutprivatebrowsing"
-  );
+  new window.ContentSearchHandoffUIController();
 });

--- a/browser/components/privatebrowsing/content/aboutPrivateBrowsing.xhtml
+++ b/browser/components/privatebrowsing/content/aboutPrivateBrowsing.xhtml
@@ -10,17 +10,17 @@
   <head>
     <meta http-equiv="Content-Security-Policy" content="default-src chrome: blob:; object-src 'none'"/>
     <link rel="icon" type="image/png" href="chrome://browser/skin/privatebrowsing/favicon.svg"/>
     <link rel="stylesheet" href="chrome://browser/content/aboutPrivateBrowsing.css" type="text/css" media="all"/>
     <link rel="stylesheet" href="chrome://browser/skin/privatebrowsing/aboutPrivateBrowsing.css" type="text/css" media="all"/>
     <link rel="localization" href="branding/brand.ftl"/>
     <link rel="localization" href="browser/aboutPrivateBrowsing.ftl"/>
     <script src="chrome://browser/content/aboutPrivateBrowsing.js"></script>
-    <script src="chrome://browser/content/contentSearchUI.js"></script>
+    <script src="chrome://browser/content/contentSearchHandoffUI.js"></script>
   </head>
 
   <body>
     <p class="showNormal" data-l10n-id="about-private-browsing-not-private"></p>
     <button id="startPrivateBrowsing"
             class="showNormal" data-l10n-id="privatebrowsingpage-open-private-window-label"></button>
     <div id="search-banner" class="search-banner"
          hidden="true">
@@ -45,17 +45,16 @@
         <div class="wordmark" />
       </div>
       <div class="search-inner-wrapper">
         <button id="search-handoff-button" class="search-handoff-button" tabindex="-1" data-l10n-id="about-private-browsing">
           <div class="fake-textbox" data-l10n-id="about-private-browsing-search-placeholder"></div>
           <input id="fake-editable" class="fake-editable" tabindex="-1" aria-hidden="true" />
           <div class="fake-caret" />
         </button>
-        <input id="dummy-input" class="dummy-input" type="search" />
       </div>
       <div class="info">
         <h1 data-l10n-id="about-private-browsing-info-title"></h1>
         <p data-l10n-id="about-private-browsing-info-description"></p>
         <a id="private-browsing-myths" data-l10n-id="about-private-browsing-info-myths"></a>
       </div>
     </div>
   </body>

--- a/browser/modules/ContentSearch.jsm
+++ b/browser/modules/ContentSearch.jsm
@@ -448,16 +448,27 @@ var ContentSearch = {
   },
 
   _onMessageGetState(msg, data) {
     return this.currentStateObj(msg.target.ownerGlobal).then(state => {
       this._reply(msg, "State", state);
     });
   },
 
+  _onMessageGetEngine(msg, data) {
+    return this.currentStateObj(msg.target.ownerGlobal).then(state => {
+      this._reply(msg, "Engine", {
+        isPrivateWindow: state.isPrivateWindow,
+        engine: state.isPrivateWindow
+          ? state.currentPrivateEngine
+          : state.currentEngine,
+      });
+    });
+  },
+
   _onMessageGetStrings(msg, data) {
     this._reply(msg, "Strings", this.searchSuggestionUIStrings);
   },
 
   _onMessageSearch(msg, data) {
     this.performSearch(msg, data);
   },
 

--- a/browser/themes/shared/privatebrowsing/aboutPrivateBrowsing.css
+++ b/browser/themes/shared/privatebrowsing/aboutPrivateBrowsing.css
@@ -158,20 +158,16 @@ p {
   display: none;
   inset-inline-start: 47px;
   height: 17px;
   position: absolute;
   top: 16px;
   width: 1px;
 }
 
-.dummy-input {
-  display: none;
-}
-
 .search-banner {
   width: 100%;
   background-color: var(--in-content-banner-background);
   color: var(--in-content-banner-text-color);
 }
 
 .banner-body {
   margin: auto;