build(bazel): Turning on strictPropertyInitialization for Angular. (#24572)

All errors for existing fields have been detected and suppressed with a
`!` assertion.

Issue/24571 is tracking proper clean up of those instances.

One-line change required in ivy/compilation.ts, because it appears that
the new syntax causes tsickle emitted node to no longer track their
original sourceFiles.

PR Close #24572

packages/platform-browser/src/browser/location/browser_platform_location.ts

@@ -23,8 +23,10 @@ import {supportsState} from './history';
  */
 @Injectable()
 export class BrowserPlatformLocation extends PlatformLocation {
-  public readonly location: Location;
-  private _history: History;
+  // TODO(issue/24571): remove '!'.
+  public readonly location !: Location;
+  // TODO(issue/24571): remove '!'.
+  private _history !: History;
 
   constructor(@Inject(DOCUMENT) private _doc: any) {
     super();

packages/platform-browser/src/dom/dom_adapter.ts

@@ -50,7 +50,8 @@ export abstract class DomAdapter {
   get attrToPropMap(): {[key: string]: string} { return this._attrToPropMap; }
   set attrToPropMap(value: {[key: string]: string}) { this._attrToPropMap = value; }
   /** @internal */
-  _attrToPropMap: {[key: string]: string};
+  // TODO(issue/24571): remove '!'.
+  _attrToPropMap !: {[key: string]: string};
 
   abstract contains(nodeA: any, nodeB: any): boolean;
   abstract parse(templateHtml: string): any;

packages/platform-browser/src/dom/events/event_manager.ts

@@ -88,7 +88,8 @@ export class EventManager {
 export abstract class EventManagerPlugin {
   constructor(private _doc: any) {}
 
-  manager: EventManager;
+  // TODO(issue/24571): remove '!'.
+  manager !: EventManager;
 
   abstract supports(eventName: string): boolean;