feat(modal): allow users to resolve with strings

- Allows users to specify a string reference to a service for injection

Closes #2676
Closes #4124

Author: wesleycho

Diff for: src/modal/modal.js

@@ -538,6 +538,8 @@ angular.module('ui.bootstrap.modal', [])
             angular.forEach(resolves, function (value) {
               if (angular.isFunction(value) || angular.isArray(value)) {
                 promisesArr.push($q.when($injector.invoke(value)));
+              } else if (angular.isString(value)) {
+                promisesArr.push($q.when($injector.get(value)));
               }
             });
             return promisesArr;

Diff for: src/modal/test/modal.spec.js

@@ -547,6 +547,21 @@ describe('$modal', function () {
         expect($document).toHaveModalOpenWithContent('Content from resolve', 'div');
       });
 
+      it('should resolve string references to injectables', function () {
+        open({
+          controller: function($scope, $foo) {
+            $scope.value = 'Content from resolve';
+            expect($foo).toBe($modal);
+          },
+          resolve: {
+            $foo: '$modal'
+          },
+          template: '<div>{{value}}</div>'
+        });
+
+        expect($document).toHaveModalOpenWithContent('Content from resolve', 'div');
+      });
+
       it('should delay showing modal if one of the resolves is a promise', function () {
 
         open(modalDefinition('<div>{{value}}</div>', {