fix(orderBy): support string predicates containing non-ident characters

The orderBy filter now allows string predicates passed to the orderBy filter to make use property
name predicates containing non-ident strings, such as spaces or percent signs, or non-latin
characters.

Closes angular#6143

src/ng/filter/orderBy.js

@@ -73,10 +73,10 @@ function orderByFilter($parse){
           descending = predicate.charAt(0) == '-';
           predicate = predicate.substring(1);
         }
-        get = $parse(predicate);
+        get = $parse('item["'+predicate+'"]');
       }
       return reverseComparator(function(a,b){
-        return compare(get(a),get(b));
+        return compare(get(a, {'item': a}),get(b, {'item': b}));
       }, descending);
     });
     var arrayCopy = [];

test/ng/filter/orderBySpec.js

@@ -31,4 +31,8 @@ describe('Filter: orderBy', function() {
     toEqual([{a:2, b:1},{a:15, b:1}]);
   });
 
+  it('should support string predicates with names containing non-identifier characters', function() {
+    expect(orderBy([{"Tip %": .25}, {"Tip %": .15}, {"Tip %": .40}], 'Tip %'))
+      .toEqualData([{"Tip %": .15}, {"Tip %": .25}, {"Tip %": .40}]);
+  });
 });