Implement {Start,Stop}CapturingKeyStrokes for Instant.

chrome/renderer/resources/extensions/searchbox/searchbox_api.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var chrome;
 if (!chrome)
   chrome = {};
 if (!chrome.searchBox) {
   chrome.searchBox = new function() {
     // =========================================================================
@@ skipping 20 matching lines @@
     native function GetAutocompleteResults();
     native function GetIsFocused();
     native function GetContext();
     native function NavigateContentWindow();
     native function SetSuggestions();
     native function SetQuerySuggestion();
     native function SetQuerySuggestionFromAutocompleteResult();
     native function SetQuery();
     native function SetQueryFromAutocompleteResult();
     native function Show();
+    native function WebSearchBoxGotFocus();
+    native function WebSearchBoxLostFocus();
 
     // Returns the |restrictedText| wrapped in a ShadowDOM.
     function SafeWrap(restrictedText) {
       var node = document.createElement('div');
       var nodeShadow = new WebKitShadowRoot(node);
       nodeShadow.applyAuthorStyles = true;
       nodeShadow.innerHTML =
           '<div style="width:700px!important;' +
           '            height:22px!important;' +
           '            font-family:\'Chrome Droid Sans\',\'Arial\'!important;' +
@@ skipping 143 matching lines @@
     };
     this.show = function(reason, height) {
       Show(reason, height);
     };
     this.markDuplicateSuggestions = function(clientSuggestions) {
       return DedupeClientSuggestions(clientSuggestions);
     };
     this.navigateContentWindow = function(destination) {
       return NavigateContentWindow(destination);
     };
+    this.webSearchBoxGotFocus = function() {
+      WebSearchBoxGotFocus();
+    };
+    this.webSearchBoxLostFocus = function() {
+      WebSearchBoxLostFocus();
+    };
     this.onchange = null;
     this.onsubmit = null;
     this.oncancel = null;
     this.onresize = null;
     this.onautocompleteresults = null;
     this.onkeypress = null;
     this.onfocus = null;
     this.onblur = null;
     this.oncontextchange = null;
   };
 }