🐛 Move ampDoc references into amp-story buildCallback (ampproject#30986)

* Move methods that need ampdoc to buildCallback.

* Update types.

* Remove const

* Fix typo.

* devAssert.

extensions/amp-story/1.0/amp-story.js

@@ -327,13 +327,14 @@ export class AmpStory extends AMP.BaseElement {
     /** @private @const {!../../../src/service/platform-impl.Platform} */
     this.platform_ = Services.platformFor(this.win);
 
-    /** @private @const {!../../../src/service/viewer-interface.ViewerInterface} */
-    this.viewer_ = Services.viewerForDoc(this.element);
+    /** @private {?../../../src/service/viewer-interface.ViewerInterface} */
+    this.viewer_ = null;
 
-    /** @private @const {?AmpStoryViewerMessagingHandler} */
-    this.viewerMessagingHandler_ = this.viewer_.isEmbedded()
-      ? new AmpStoryViewerMessagingHandler(this.win, this.viewer_)
-      : null;
+    /** @private {?AmpStoryViewerMessagingHandler} */
+    this.viewerMessagingHandler_ = null;
+
+    /** @private {?../../../src/service/localization.LocalizationService} */
+    this.localizationService_ = null;
 
     /**
      * Store the current paused state, to make sure the story does not play on
@@ -353,8 +354,16 @@ export class AmpStory extends AMP.BaseElement {
 
     /** @private {?LiveStoryManager} */
     this.liveStoryManager_ = null;
+  }
+
+  /** @override */
+  buildCallback() {
+    this.viewer_ = Services.viewerForDoc(this.element);
+
+    this.viewerMessagingHandler_ = this.viewer_.isEmbedded()
+      ? new AmpStoryViewerMessagingHandler(this.win, this.viewer_)
+      : null;
 
-    /** @private @const {!../../../src/service/localization.LocalizationService} */
     this.localizationService_ = getLocalizationService(this.element);
 
     this.localizationService_
@@ -389,10 +398,7 @@ export class AmpStory extends AMP.BaseElement {
       'en-xa',
       enXaPseudoLocaleBundle
     );
-  }
 
-  /** @override */
-  buildCallback() {
     if (this.isStandalone_()) {
       this.initializeStandaloneStory_();
     }
@@ -1003,7 +1009,7 @@ export class AmpStory extends AMP.BaseElement {
         // Preloads and prerenders the share menu.
         this.shareMenu_.build();
 
-        const infoDialog = shouldShowStoryUrlInfo(this.viewer_)
+        const infoDialog = shouldShowStoryUrlInfo(devAssert(this.viewer_))
           ? new InfoDialog(this.win, this.element)
           : null;
         if (infoDialog) {