fix(docs): don't throw exception on the 404 page

Closes #8518

docs/app/e2e/docsAppE2E.js

@@ -1,6 +1,24 @@
 'use strict';
 
 describe('docs.angularjs.org', function () {
+
+  beforeEach(function() {
+    // read and clear logs from previous tests
+    browser.manage().logs().get('browser');
+  });
+
+
+  afterEach(function() {
+    // verify that there were no console errors in the browser
+    browser.manage().logs().get('browser').then(function(browserLog) {
+      expect(browserLog.length).toEqual(0);
+      if (browserLog.length) {
+        console.log('browser console errors: ' + require('util').inspect(browserLog));
+      }
+    });
+  });
+
+
   describe('App', function () {
     // it('should filter the module list when searching', function () {
     //   browser.get();
@@ -67,6 +85,12 @@ describe('docs.angularjs.org', function () {
       browser.get('index-debug.html#!error/ng/areq?p0=Missing&p1=not%20a%20function,%20got%20undefined');
       expect(element(by.css('.minerr-errmsg')).getText()).toEqual("Argument 'Missing' is not a function, got undefined");
     });
+
+
+    it("should display links to code on GitHub", function() {
+      browser.get('index-debug.html#!/api/does/not/exist');
+      expect(element(by.css('h1')).getText()).toBe('Oops!');
+    });
   });
 
   describe("templates", function() {

docs/app/src/docs.js

@@ -33,7 +33,7 @@ angular.module('DocsController', [])
 
   $scope.navClass = function(navItem) {
     return {
-      active: navItem.href && this.currentPage.path,
+      active: navItem.href && this.currentPage && this.currentPage.path,
       'nav-index-section': navItem.type === 'section'
     };
   };