[MD History] Add history-searched-label to embolden the synced device search.

chrome/browser/resources/md_history/searched_label.js

+// Copyright 2016 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.
+
+Polymer({
+  is: 'history-searched-label',
+
+  properties: {
+    // The text to show in this label.
+    title: String,
+
+    // The search term to bold within the title.
+    searchTerm: String,
+  },
+
+  observers: ['setSearchedTextToBold_(title, searchTerm)'],
+
+  /**
+   * Updates the page title. If a search term is specified, highlights any
+   * occurrences of the search term in bold.
+   * @private
+   */
+  setSearchedTextToBold_: function() {
+    var i = 0;
+    var titleElem = this.$.container;
+    var titleText = this.title;
+
+    if (this.searchTerm == '' || this.searchTerm == null) {
+      titleElem.textContent = titleText;
+      return;
+    }
+
+    var re = new RegExp(quoteString(this.searchTerm), 'gim');
+    var match;
+    titleElem.textContent = '';
+    while (match = re.exec(titleText)) {
+      if (match.index > i)
+        titleElem.appendChild(document.createTextNode(
+            titleText.slice(i, match.index)));
+      i = re.lastIndex;
+      // Mark the highlighted text in bold.
+      var b = document.createElement('b');
+      b.textContent = titleText.substring(match.index, i);
+      titleElem.appendChild(b);
+    }
+    if (i < titleText.length)
+      titleElem.appendChild(
+          document.createTextNode(titleText.slice(i)));
+  },
+});