MD History: Announce search results for screen-reader users

This adds a screen reader announcement of "Found X search results for
'Y'" when the user performs a search.

BUG=425625,606527
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2388413002
Cr-Commit-Position: refs/heads/master@{#423062}

chrome/browser/resources/md_history/history_item.js

@@ -289,18 +289,16 @@ cr.define('md_history', function() {
     },
 
     /**
-     * Generates the title for this history card.
      * @param {number} numberOfItems The number of items in the card.
+     * @param {string} historyDate Date of the current result.
      * @param {string} search The search term associated with these results.
+     * @return {string} The title for this history card.
      * @private
      */
     cardTitle_: function(numberOfItems, historyDate, search) {
       if (!search)
         return this.item.dateRelativeDay;
-
-      var resultId = numberOfItems == 1 ? 'searchResult' : 'searchResults';
-      return loadTimeData.getStringF('foundSearchResults', numberOfItems,
-          loadTimeData.getString(resultId), search);
+      return HistoryItem.searchResultsTitle(numberOfItems, search);
     },
   });
 
@@ -311,7 +309,6 @@ cr.define('md_history', function() {
    * @param {number} currentIndex
    * @param {string} searchedTerm
    * @return {boolean} Whether or not time gap separator is required.
-   * @private
    */
   HistoryItem.needsTimeGap = function(visits, currentIndex, searchedTerm) {
     if (currentIndex >= visits.length - 1 || visits.length == 0)
@@ -327,5 +324,16 @@ cr.define('md_history', function() {
         currentItem.dateRelativeDay == nextItem.dateRelativeDay;
   };
 
+  /**
+   * @param {number} numberOfResults
+   * @param {string} searchTerm
+   * @return {string} The title for a page of search results.
+   */
+  HistoryItem.searchResultsTitle = function(numberOfResults, searchTerm) {
+    var resultId = numberOfResults == 1 ? 'searchResult' : 'searchResults';
+    return loadTimeData.getStringF('foundSearchResults', numberOfResults,
+        loadTimeData.getString(resultId), searchTerm);
+  };
+
   return { HistoryItem: HistoryItem };
 });

chrome/browser/resources/md_history/list_container.js

@@ -41,6 +41,11 @@ Polymer({
     this.initializeResults_(info, results);
     this.closeMenu_();
 
+    if (info.term && !this.queryState.incremental) {
+      announceAccessibleMessage(
+          md_history.HistoryItem.searchResultsTitle(results.length, info.term));
+    }
+
     if (this.selectedPage_ == 'grouped-list') {
       this.$$('#grouped-list').historyData = results;
       return;

ui/webui/resources/js/util.js

@@ -35,7 +35,7 @@ function getSVGElement(id) {
 function announceAccessibleMessage(msg) {
   var element = document.createElement('div');
   element.setAttribute('aria-live', 'polite');
-  element.style.position = 'relative';
+  element.style.position = 'fixed';
   element.style.left = '-9999px';
   element.style.height = '0px';
   element.innerText = msg;