fix(reflector): merge prop metadata from getters and setters

Closes #4006

modules/angular2/src/core/reflection/reflection_capabilities.dart

@@ -259,7 +259,8 @@ class ReflectionCapabilities implements PlatformReflectionCapabilities {
     final res = {};
     reflectClass(typeOrFunc).declarations.forEach((k,v) {
       var name = _normalizeName(MirrorSystem.getName(k));
-      res[name] = v.metadata.map((fm) => fm.reflectee).toList();
+      if (res[name] == null) res[name] = [];
+      res[name].addAll(v.metadata.map((fm) => fm.reflectee));
     });
     return res;
   }

modules/angular2/test/core/reflection/reflector_common.dart

@@ -27,3 +27,8 @@ ParamDecorator paramDecorator(value) {
 PropDecorator propDecorator(value) {
   return new PropDecorator(value);
 }
+
+class HasGetterAndSetterDecorators {
+  @PropDecorator("get") get a {}
+  @PropDecorator("set") set a(v) {}
+}

modules/angular2/test/core/reflection/reflector_common.ts

@@ -31,3 +31,6 @@ export function propDecorator(value) {
 export var ClassDecorator = makeDecorator(ClassDecoratorMeta);
 export var ParamDecorator = makeParamDecorator(ParamDecoratorMeta);
 export var PropDecorator = makePropDecorator(PropDecoratorMeta);
+
+// used only in Dart
+export class HasGetterAndSetterDecorators {}

modules/angular2/test/core/reflection/reflector_spec.ts

@@ -7,7 +7,8 @@ import {
   PropDecorator,
   classDecorator,
   paramDecorator,
-  propDecorator
+  propDecorator,
+  HasGetterAndSetterDecorators
 } from './reflector_common';
 import {IS_DART} from '../../platform';
 
@@ -160,6 +161,13 @@ export function main() {
         reflector.registerType(TestObj, new ReflectionInfo(null, null, null, null, {"a": [1, 2]}));
         expect(reflector.propMetadata(TestObj)).toEqual({"a": [1, 2]});
       });
+
+      if (IS_DART) {
+        it("should merge metadata from getters and setters", () => {
+          var p = reflector.propMetadata(HasGetterAndSetterDecorators);
+          expect(p["a"]).toEqual([propDecorator("get"), propDecorator("set")]);
+        });
+      }
     });
 
     describe("annotations", () => {