feat(forms): add support for disabled controls (#10994)

modules/@angular/forms/src/directives/reactive_errors.ts

@@ -61,4 +61,18 @@ export class ReactiveErrors {
 
         ${Examples.formArrayName}`);
   }
+
+  static disabledAttrWarning(): void {
+    console.warn(`
+      It looks like you're using the disabled attribute with a reactive form directive. If you set disabled to true
+      when you set up this control in your component class, the disabled attribute will actually be set in the DOM for
+      you. We recommend using this approach to avoid 'changed after checked' errors.
+       
+      Example: 
+      form = new FormGroup({
+        first: new FormControl({value: 'Nancy', disabled: true}, Validators.required),
+        last: new FormControl('Drew', Validators.required)
+      });
+    `);
+  }
 }