Enforce explicit WebGL book playback timeline

public/js/ui-display-handler-module.js

@@ -71,7 +71,6 @@ class UIDisplayHandlerModule extends BaseModule {
             'isWebGLMode',
             'playWebGLBookSentence',
             'prepareWebGLBookReveal',
-            'waitForWebGLPageFlip',
             'renderStoryBlock',
             'prepareRenderableBlock',
             'prepareTextRenderable',
@@ -1070,47 +1069,6 @@ class UIDisplayHandlerModule extends BaseModule {
         return timeline.prepareSentence(sentence, { immediate: true });
     }
 
-    waitForWebGLPageFlip(detail = {}) {
-        return new Promise((resolve) => {
-            let resolved = false;
-            const cleanup = () => {
-                window.clearTimeout(timeout);
-                document.removeEventListener('webgl-book:page-flip-started', onStarted);
-                document.removeEventListener('webgl-book:page-flip-finished', onFinished);
-            };
-            const finish = (result) => {
-                if (resolved) return;
-                resolved = true;
-                cleanup();
-                resolve(result);
-            };
-            const requestedTargetSpread = Number.isFinite(Number(detail.targetSpread))
-                ? Math.max(0, Math.round(Number(detail.targetSpread)))
-                : null;
-            const matchesTarget = (eventDetail = {}) => requestedTargetSpread == null
-                || Math.max(0, Math.round(Number(eventDetail.targetSpread || 0))) === requestedTargetSpread;
-            const onStarted = (event) => {
-                if (!matchesTarget(event.detail || {})) return;
-                document.documentElement.dataset.webglLastStartedPageFlip = JSON.stringify(event.detail || {});
-            };
-            const onFinished = (event) => {
-                if (!matchesTarget(event.detail || {})) return;
-                finish(true);
-            };
-            const timeout = window.setTimeout(() => finish(false), 2400);
-            document.addEventListener('webgl-book:page-flip-started', onStarted);
-            document.addEventListener('webgl-book:page-flip-finished', onFinished);
-            document.dispatchEvent(new CustomEvent('webgl-book:request-page-flip', {
-                detail: {
-                    direction: Math.sign(Number(detail.direction || 1)) || 1,
-                    reason: detail.reason || 'pending-block-overflow',
-                    force: true,
-                    targetSpread: requestedTargetSpread
-                }
-            }));
-        });
-    }
-
     async rerenderStory() {
         if (!this.paragraphContainer || this.renderedItems.length === 0) return;
         console.log('UIDisplayHandler: Re-typesetting story after page resize');