fix(ui-grid.js): gridOptions.data string value now works again.

Added back if statement in the dataWatchFunction and added an $eval to ensure controllerAs systax is
supported.

fix #6377, fix #6155

Author: Portugal, Marcelo

misc/tutorial/106_binding.ngdoc

@@ -28,6 +28,15 @@ For better performance with the following example, you can choose to load the ui
     app.controller('MainCtrl', function MainCtrl() {
       var vm = this;
 
+      vm.myData = [
+        {
+          'first-name': 'Cox',
+          friends: ['friend0'],
+          address: {street: '301 Dove Ave', city: 'Laurel', zip: '39565'},
+          getZip: function() {return this.address.zip;}
+								}
+						];
+
       vm.gridOptions = {
         enableSorting: true,
         columnDefs: [
@@ -36,14 +45,7 @@ For better performance with the following example, you can choose to load the ui
           { name:'city', field: 'address.city'},
           { name:'getZip', field: 'getZip()', enableCellEdit: false}
         ],
-        data: [
-          {
-            'first-name': 'Cox',
-            friends: ['friend0'],
-            address: {street: '301 Dove Ave', city: 'Laurel', zip: '39565'},
-            getZip: function() {return this.address.zip;}
-          }
-        ]
+        data: '$ctrl.myData'
       };
     });
   </file>

src/js/core/directives/ui-grid.js

@@ -84,10 +84,12 @@
         // gridUtil.logDebug('dataWatch fired');
         var promises = [];
 
-        if (angular.isString($scope.uiGrid.data)) {
-          newData = self.grid.appScope[$scope.uiGrid.data];
-        } else {
-          newData = $scope.uiGrid.data;
+        if ( self.grid.options.fastWatch ) {
+          if (angular.isString($scope.uiGrid.data)) {
+            newData = self.grid.appScope.$eval($scope.uiGrid.data);
+          } else {
+            newData = $scope.uiGrid.data;
+          }
         }
 
         mostRecentData = newData;