feat: remove MapWrapper.contains().

modules/angular2/src/render/dom/shadow_dom/util.ts

@@ -20,7 +20,7 @@ export function getComponentId(componentStringId: string) {
 }
 
 export function insertSharedStyleText(cssText, styleHost, styleEl) {
-  if (!MapWrapper.contains(_sharedStyleTexts, cssText)) {
+  if (!_sharedStyleTexts.has(cssText)) {
     // Styles are unscoped and shared across components, only append them to the head
     // when there are not present yet
     _sharedStyleTexts.set(cssText, true);

modules/angular2/src/render/xhr_mock.ts

@@ -65,7 +65,7 @@ export class MockXHR extends XHR {
       }
     }
 
-    if (MapWrapper.contains(this._definitions, url)) {
+    if (this._definitions.has(url)) {
       var response = this._definitions.get(url);
       request.complete(normalizeBlank(response));
       return;