CrSearchFieldBehavior: Fix case where infinite 'search-changed' events are fired.

chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.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.
 
 /** @fileoverview Suite of tests for cr-toolbar-search-field. */
 cr.define('cr_toolbar_search_field', function() {
   function registerTests() {
     suite('cr-toolbar-search-field', function() {
       /** @type {?CrToolbarSearchFieldElement} */
       var field = null;
@@ skipping 75 matching lines @@
         MockInteractions.tap(field);
         field.setValue('foo');
         field.setValue('');
         field.setValue('bar');
         // Expecting identical query to be ignored.
         field.setValue('bar');
         field.setValue('baz');
         assertEquals(['foo', '', 'bar', 'baz'].join(), searches.join());
       });
 
+      // Tests that calling setValue() from within a 'search-changed' callback
+      // does not result in an infinite loop.
+      test('no infinite loop', function() {
+        var counter = 0;
+        field.addEventListener('search-changed', function(event) {
+          counter++;
+          // Calling setValue() with the already existing value should not
+          // trigger another 'search-changed' event.
+          field.setValue(event.detail);
+        });
+
+        MockInteractions.tap(field);
+        field.setValue('bar');
+        assertEquals(1, counter);
+        assertEquals(['bar'].join(), searches.join());
+      });
+
       test('blur does not close field when a search is active', function() {
         MockInteractions.tap(field);
         simulateSearch('test');
         MockInteractions.blur(field.$.searchInput);
 
         assertTrue(field.showingSearch);
       });
 
       test('opens when value is changed', function() {
         // Change search value without explicity opening the field first.
         // Similar to what happens when pasting or dragging into the input
         // field.
         simulateSearch('test');
         Polymer.dom.flush();
 
         var clearSearch = field.$$('#clearSearch');
         assertFalse(clearSearch.hidden);
         assertTrue(field.showingSearch);
       });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });