Prevent bogus 'search-changed' event firing from cr_search_field_behavior.js.

ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js

Index: ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js
diff --git a/ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js b/ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js
index a5137e88ed11bf0d83c53d3f53eec68535092ea2..d87184144f6312a9d830bf2adeda1e446edddfc9 100644
--- a/ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js
+++ b/ui/webui/resources/cr_elements/cr_search_field/cr_search_field_behavior.js
@@ -92,8 +92,16 @@ var CrSearchFieldBehavior = {
       this.showingSearch = false;
   },
 
-  /** @private */
-  showingSearchChanged_: function() {
+  /**
+   * @param {boolean} current
+   * @param {boolean|undefined} previous
+   * @private
+   */
+  showingSearchChanged_: function(current, previous) {
+    // Prevent unnecessary 'search-changed' event from firing on startup.
+    if (previous == undefined)
+      return;
+
     if (this.showingSearch) {
       this.focus_();
       return;