diff --git a/packages/elements/src/create-custom-element.ts b/packages/elements/src/create-custom-element.ts
index 8159c43b3d..2e1069840f 100644
--- a/packages/elements/src/create-custom-element.ts
+++ b/packages/elements/src/create-custom-element.ts
@@ -144,9 +144,8 @@ export function createCustomElement<P>(
       //
       // TODO(andrewseguin): Add e2e tests that cover cases where the constructor isn't called. For
       // now this is tested using a Google internal test suite.
-      if (!this._ngElementStrategy) {
-        const strategy = this._ngElementStrategy =
-            strategyFactory.create(this.injector || config.injector);
+      if (this._ngElementStrategy === null) {
+        const strategy = this._ngElementStrategy = strategyFactory.create(this.injector);
 
         // Collect pre-existing values on the element to re-apply through the strategy.
         const preExistingValues =
@@ -174,10 +173,12 @@ export function createCustomElement<P>(
       return this._ngElementStrategy!;
     }
 
-    private _ngElementStrategy?: NgElementStrategy;
+    private readonly injector: Injector;
+    private _ngElementStrategy: NgElementStrategy|null = null;
 
-    constructor(private readonly injector?: Injector) {
+    constructor(injector?: Injector) {
       super();
+      this.injector = injector || config.injector;
     }
 
     attributeChangedCallback(
diff --git a/packages/elements/test/create-custom-element_spec.ts b/packages/elements/test/create-custom-element_spec.ts
index 3f9dcd5eaf..3551084d72 100644
--- a/packages/elements/test/create-custom-element_spec.ts
+++ b/packages/elements/test/create-custom-element_spec.ts
@@ -73,26 +73,6 @@ if (browserDetection.supportsCustomElements) {
       expect(strategy.getInputValue('barBar')).toBe('value-barbar');
     });
 
-    it('should work even if when the constructor is not called (due to polyfill)', () => {
-      // Some polyfills (e.g. `document-register-element`) do not call the constructor of custom
-      // elements. Currently, all the constructor does is initialize the `injector` property. This
-      // test simulates not having called the constructor by "unsetting" the property.
-      //
-      // NOTE:
-      // If the constructor implementation changes in the future, this test needs to be adjusted
-      // accordingly.
-      const element = new NgElementCtor(injector);
-      delete (element as any).injector;
-
-      element.setAttribute('foo-foo', 'value-foo-foo');
-      element.setAttribute('barbar', 'value-barbar');
-      element.connectedCallback();
-
-      expect(strategy.connectedElement).toBe(element);
-      expect(strategy.getInputValue('fooFoo')).toBe('value-foo-foo');
-      expect(strategy.getInputValue('barBar')).toBe('value-barbar');
-    });
-
     it('should listen to output events after connected', () => {
       const element = new NgElementCtor(injector);
       element.connectedCallback();
@@ -280,14 +260,7 @@ if (browserDetection.supportsCustomElements) {
     class TestStrategyFactory implements NgElementStrategyFactory {
       testStrategy = new TestStrategy();
 
-      create(injector: Injector): NgElementStrategy {
-        // Although not used by the `TestStrategy`, verify that the injector is provided.
-        if (!injector) {
-          throw new Error(
-              'Expected injector to be passed to `TestStrategyFactory#create()`, but received ' +
-              `value of type ${typeof injector}: ${injector}`);
-        }
-
+      create(): NgElementStrategy {
         return this.testStrategy;
       }
     }