fix(ngClass): fix watching of an array expression containing an object

Closes #14405

src/ng/directive/ngClass.js

@@ -78,7 +78,11 @@ function classDirective(name, selector) {
               updateClasses(oldClasses, newClasses);
             }
           }
-          oldVal = shallowCopy(newVal);
+          if (isArray(newVal)) {
+            oldVal = newVal.map(function(v) { return shallowCopy(v); });
+          } else {
+            oldVal = shallowCopy(newVal);
+          }
         }
       }
     };

test/ng/directive/ngClassSpec.js

@@ -409,6 +409,22 @@ describe('ngClass', function() {
     expect(e2.hasClass('even')).toBeTruthy();
     expect(e2.hasClass('odd')).toBeFalsy();
   }));
+
+  it('should support mixed array/object variable with a mutating object',
+    inject(function($rootScope, $compile) {
+      element = $compile('<div ng-class="classVar"></div>')($rootScope);
+
+      $rootScope.classVar = [{orange: true}];
+      $rootScope.$digest();
+      expect(element).toHaveClass('orange');
+
+      $rootScope.classVar[0].orange = false;
+      $rootScope.$digest();
+
+      expect(element).not.toHaveClass('orange');
+    })
+  );
+
 });
 
 describe('ngClass animations', function() {