chore(ngdocs): allow user to press escape key to close docs search

docs/src/templates/index.html

@@ -173,8 +173,14 @@
             <li class="divider-vertical"></li>
           </ul>
           <form class="navbar-search pull-right" ng-submit="submit()">
-            <input type="text" name="as_q" class="search-query" placeholder="Search" ng-change="search(q)" ng-model="q" autocomplete="off">
-            <input type="hidden" name="as_sitesearch" value="angularjs.org">
+            <input type="text"
+                   name="as_q"
+                   class="search-query"
+                   placeholder="Search"
+                   ng-change="search(q)"
+                   ng-model="q"
+                   docs-search-input
+                   autocomplete="off" />
           </form>
           <div ng-show="hasResults" class="search-results">
             <a href="" ng-click="hideResults()" class="search-close">

docs/src/templates/js/docs.js

@@ -138,6 +138,21 @@ docsApp.directive.focused = function($timeout) {
   };
 };
 
+docsApp.directive.docsSearchInput = function() {
+  return function(scope, element, attrs) {
+    var ESCAPE_KEY_KEYCODE = 27;
+    element.bind('keydown', function(event) {
+      if(event.keyCode == ESCAPE_KEY_KEYCODE) {
+        event.stopPropagation();
+        event.preventDefault();
+        scope.$apply(function() {
+          scope.hideResults();
+        });
+      }
+    });
+  };
+};
+
 
 docsApp.directive.code = function() {
   return { restrict:'E', terminal: true };