build: set up API golden file for youtube-player package (#17426)

Now that the `youtube-player` package has been released, we need an API golden file to make sure that we don't make any unintended API changes.

Author: crisbeto

.github/CODEOWNERS

@@ -294,6 +294,7 @@
 /tools/public_api_guard/material/tooltip.d.ts           @andrewseguin
 /tools/public_api_guard/material/tree.d.ts              @jelbourn @andrewseguin
 /tools/public_api_guard/material/material.d.ts          @jelbourn
+/tools/public_api_guard/youtube-player/youtube-player.d.ts      @jelbourn @nathantate
 
 # Misc
 /*                                                 @angular/dev-infra-components @jelbourn

tools/public_api_guard/generate-guard-tests.bzl

@@ -31,4 +31,6 @@ def generate_test_targets(golden_files):
             ],
             golden = "angular_material/tools/public_api_guard/%s" % golden_file,
             use_angular_tag_rules = False,
+            # Required for the `youtube-player` package.
+            allow_module_identifiers = ["YT"],
         )

tools/public_api_guard/youtube-player/youtube-player.d.ts

@@ -0,0 +1,44 @@
+export declare class YouTubePlayer implements AfterViewInit, OnDestroy, OnInit {
+    apiChange: EventEmitter<YT.PlayerEvent>;
+    endSeconds: number | undefined;
+    error: EventEmitter<YT.OnErrorEvent>;
+    height: number | undefined;
+    playbackQualityChange: EventEmitter<YT.OnPlaybackQualityChangeEvent>;
+    playbackRateChange: EventEmitter<YT.OnPlaybackRateChangeEvent>;
+    ready: EventEmitter<YT.PlayerEvent>;
+    showBeforeIframeApiLoads: boolean | undefined;
+    startSeconds: number | undefined;
+    stateChange: EventEmitter<YT.OnStateChangeEvent>;
+    suggestedQuality: YT.SuggestedVideoQuality | undefined;
+    videoId: string | undefined;
+    width: number | undefined;
+    youtubeContainer: ElementRef<HTMLElement>;
+    constructor(_ngZone: NgZone);
+    createEventsBoundInZone(): YT.Events;
+    getAvailablePlaybackRates(): number[];
+    getAvailableQualityLevels(): YT.SuggestedVideoQuality[];
+    getCurrentTime(): number;
+    getDuration(): number;
+    getPlaybackQuality(): YT.SuggestedVideoQuality;
+    getPlaybackRate(): number;
+    getPlayerState(): YT.PlayerState | undefined;
+    getVideoEmbedCode(): string;
+    getVideoLoadedFraction(): number;
+    getVideoUrl(): string;
+    getVolume(): number;
+    isMuted(): boolean;
+    mute(): void;
+    ngAfterViewInit(): void;
+    ngOnDestroy(): void;
+    ngOnInit(): void;
+    pauseVideo(): void;
+    playVideo(): void;
+    seekTo(seconds: number, allowSeekAhead: boolean): void;
+    setPlaybackRate(playbackRate: number): void;
+    setVolume(volume: number): void;
+    stopVideo(): void;
+    unMute(): void;
+}
+
+export declare class YouTubePlayerModule {
+}