fix(webview): page.getContentQuads should work for elements inside <iframe>

Walk up the ancestor `<iframe>` chain, adding each frame's content-box
offset to the element's own quads. Each offset is computed in the parent
realm from `getBoundingClientRect()` plus the border/padding reported by
`describeIFrameStyle()`.

This also works for cross-origin iframes. The offsets are read from the
parent side, so no same-origin `contentDocument` access is needed; and
`getContentQuads` now propagates `error:notconnected`. A cross-origin
(out-of-process) frame's context is torn down and recreated on navigations
and process swaps, so the element handle can go stale mid-measurement.
Returning `error:notconnected` instead of `null` (which would read as
merely "not visible") lets the caller re-resolve the element in the fresh
context and retry instead of waiting out the timeout.

Author: dcrousso

packages/playwright-core/src/server/webkit/webview/wvPage.ts

@@ -824,7 +824,7 @@ export class WVPage implements PageDelegate {
 
   async getBoundingBox(handle: dom.ElementHandle): Promise<types.Rect | null> {
     const quads = await this.getContentQuads(handle);
-    if (!quads || !quads.length)
+    if (quads === 'error:notconnected' || !quads || !quads.length)
       return null;
     let minX = Infinity;
     let maxX = -Infinity;
@@ -869,7 +869,7 @@ export class WVPage implements PageDelegate {
     return 1;
   }
 
-  async getContentQuads(handle: dom.ElementHandle): Promise<types.Quad[] | null> {
+  async getContentQuads(handle: dom.ElementHandle): Promise<types.Quad[] | null | 'error:notconnected'> {
     const result = await handle.evaluateInUtility(([, node]) => {
       let element: Element | null = node as Element;
       while (element && element.nodeType !== 1 /* Node.ELEMENT_NODE */)
@@ -886,9 +886,32 @@ export class WVPage implements PageDelegate {
         { x: r.left, y: r.bottom },
       ]);
     }, {});
+    if (result === 'error:notconnected')
+      return result;
     if (!result || typeof result === 'string')
       return null;
-    return result as types.Quad[];
+    let quads = result as types.Quad[];
+    let frame: frames.Frame | null = handle._frame;
+    while (frame?.parentFrame()) {
+      const frameElement = await this.getFrameElement(frame).catch(() => null);
+      if (!frameElement)
+        return null;
+      const offset = await frameElement.evaluateInUtility(([injected, iframe]) => {
+        const element = iframe as Element;
+        const style = injected.describeIFrameStyle(element);
+        if (style === 'error:notconnected' || style === 'transformed')
+          return style;
+        const rect = element.getBoundingClientRect();
+        return { x: rect.left + style.left, y: rect.top + style.top };
+      }, {}).finally(() => frameElement.dispose());
+      if (offset === 'error:notconnected')
+        return offset;
+      if (!offset || typeof offset === 'string')
+        return null;
+      quads = quads.map(quad => quad.map(point => ({ x: point.x + offset.x, y: point.y + offset.y })) as types.Quad);
+      frame = frame.parentFrame();
+    }
+    return quads;
   }
 
   async adoptElementHandle<T extends Node>(handle: dom.ElementHandle<T>, to: dom.FrameExecutionContext): Promise<dom.ElementHandle<T>> {

tests/page/elementhandle-bounding-box.spec.ts

@@ -84,6 +84,36 @@ it('should return null for invisible elements', async ({ page, server }) => {
   expect(await element.boundingBox()).toBe(null);
 });
 
+it('should get bounding box of element inside an iframe', async ({ page, server }) => {
+  await page.goto(server.EMPTY_PAGE);
+  await page.setContent(`
+    <div style="height:120px"></div>
+    <iframe style="border:0;margin-left:30px;width:300px;height:200px" src="${server.PREFIX}/input/button.html"></iframe>
+  `);
+  const frame = page.frames()[1];
+  const button = await frame.waitForSelector('button');
+  const iframeBox = (await (await page.$('iframe')).boundingBox())!;
+  const inner = await button.evaluate(b => { const r = b.getBoundingClientRect(); return { x: r.left, y: r.top }; });
+  const box = (await button.boundingBox())!;
+  expect(Math.round(box.x)).toBe(Math.round(iframeBox.x + inner.x));
+  expect(Math.round(box.y)).toBe(Math.round(iframeBox.y + inner.y));
+});
+
+it('should get bounding box of element inside a cross-origin iframe', async ({ page, server }) => {
+  await page.goto(server.EMPTY_PAGE);
+  await page.setContent(`
+    <div style="height:120px"></div>
+    <iframe style="border:0;margin-left:30px;width:300px;height:200px" src="${server.CROSS_PROCESS_PREFIX}/input/button.html"></iframe>
+  `);
+  const frame = page.frames()[1];
+  const button = await frame.waitForSelector('button');
+  const iframeBox = (await (await page.$('iframe')).boundingBox())!;
+  const inner = await button.evaluate(b => { const r = b.getBoundingClientRect(); return { x: r.left, y: r.top }; });
+  const box = (await button.boundingBox())!;
+  expect(Math.round(box.x)).toBe(Math.round(iframeBox.x + inner.x));
+  expect(Math.round(box.y)).toBe(Math.round(iframeBox.y + inner.y));
+});
+
 it('should force a layout', async ({ page, server }) => {
   await page.setViewportSize({ width: 500, height: 500 });
   await page.setContent('<div style="width: 100px; height: 100px">hello</div>');