fix(autofill): use static queries to read values used in ngOnInit (#15574)

Author: pkozlowski-opensource

src/material-examples/text-field-autofill-monitor/text-field-autofill-monitor-example.ts

@@ -1,21 +1,21 @@
 import {AutofillMonitor} from '@angular/cdk/text-field';
-import {Component, ElementRef, OnDestroy, OnInit, ViewChild} from '@angular/core';
+import {AfterViewInit, Component, ElementRef, OnDestroy, ViewChild} from '@angular/core';
 
 /** @title Monitoring autofill state with AutofillMonitor */
 @Component({
   selector: 'text-field-autofill-monitor-example',
   templateUrl: './text-field-autofill-monitor-example.html',
   styleUrls: ['./text-field-autofill-monitor-example.css'],
 })
-export class TextFieldAutofillMonitorExample implements OnDestroy, OnInit {
+export class TextFieldAutofillMonitorExample implements AfterViewInit, OnDestroy {
   @ViewChild('first', {read: ElementRef}) firstName: ElementRef<HTMLElement>;
   @ViewChild('last', {read: ElementRef}) lastName: ElementRef<HTMLElement>;
   firstNameAutofilled: boolean;
   lastNameAutofilled: boolean;
 
   constructor(private autofill: AutofillMonitor) {}
 
-  ngOnInit() {
+  ngAfterViewInit() {
     this.autofill.monitor(this.firstName)
         .subscribe(e => this.firstNameAutofilled = e.isAutofilled);
     this.autofill.monitor(this.lastName)