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fix(screen-adapter): debounce resize handler to prevent black flicker on web

The window resize event listener in _registerEvent() was calling
_resizeFrame() synchronously on every resize event. During continuous
window dragging, this triggered dozens of swapchain/backbuffer
reallocations per second, each producing a blank (black) frame.

This change debounces the resize handler using the same EVENT_TIMEOUT
(200ms) and setTimeout pattern already used by the orientation change
handler. It also adds the handleResizeEvent guard to the DPR
matchMedia listener, which was previously bypassing it.

Fixes: #19182
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Author: UC-RX0

pal/screen-adapter/src/web/screen-adapter.ts

@@ -183,6 +183,7 @@ class ScreenAdapter extends EventTarget {
     private _onFullscreenError?: () => void;
     // We need to set timeout to handle screen event.
     private _orientationChangeTimeoutId = -1;
+    private _resizeTimeoutId = -1;
     private _cachedFrameSize = new Size(0, 0); // cache before enter fullscreen.
     private _exactFitScreen = false;
     private _isHeadlessMode = false;
@@ -381,13 +382,22 @@ class ScreenAdapter extends EventTarget {
             if (!this.handleResizeEvent) {
                 return;
             }
-            this._resizeFrame();
+            if (this._resizeTimeoutId !== -1) {
+                clearTimeout(this._resizeTimeoutId);
+            }
+            this._resizeTimeoutId = setTimeout((): void => {
+                this._resizeFrame();
+                this._resizeTimeoutId = -1;
+            }, EVENT_TIMEOUT);
         });
         if (typeof window.matchMedia === 'function') {
             const updateDPRChangeListener = (): void => {
                 const dpr = window.devicePixelRatio;
                 // NOTE: some browsers especially on iPhone doesn't support MediaQueryList
                 window.matchMedia(`(resolution: ${dpr}dppx)`)?.addEventListener?.('change', (): void => {
+                    if (!this.handleResizeEvent) {
+                        return;
+                    }
                     this.emit('window-resize', this.windowSize.width, this.windowSize.height);
                     updateDPRChangeListener();
                 }, { once: true });