Implement feedback

Add missing comment, fix comparison, add test cases.

src/browser/tests/element/bounding_rect_scroll.html

@@ -9,19 +9,21 @@
 <script id="rectIsViewportRelative">
 {
   const filler = $('#filler');
+  // Empty paragraphs have no height in a real layout, so give them text.
   for (let i = 0; i < 300; i++) {
-    filler.appendChild(document.createElement('p'));
+    const p = document.createElement('p');
+    p.textContent = 'x';
+    filler.appendChild(p);
   }
   const far = $('#far');
   const before = far.getBoundingClientRect();
   testing.expectTrue(before.top > window.innerHeight);
-  testing.expectEqual(far, document.elementFromPoint(before.x, before.y));
 
   window.scrollTo(0, 100);
   const after = far.getBoundingClientRect();
   testing.expectEqual(before.top - 100, after.top);
   testing.expectEqual(before.x, after.x);
-  testing.expectEqual(far, document.elementFromPoint(after.x, after.y));
+  testing.expectEqual(after.top, far.getClientRects()[0].top);
 
   // scrollIntoView brings it into the viewport
   far.scrollIntoView();

src/browser/webapi/Element.zig

@@ -2132,7 +2132,7 @@ pub fn scrollIntoViewIfNeeded(self: *Element, center_if_needed: ?bool, frame: *F
     const y = calculateDocumentPosition(self.asNode());
     const scroll_y: f64 = @floatFromInt(frame.window.getScrollY());
     const viewport_height: f64 = @floatFromInt(frame.window.getInnerHeight(frame));
-    if (y >= scroll_y and y <= scroll_y + viewport_height) {
+    if (y >= scroll_y and y < scroll_y + viewport_height) {
         return;
     }
     self.scrollIntoView(null, frame);

src/server/cdp/domains/dom.zig

@@ -486,6 +486,8 @@ fn scrollIntoViewIfNeeded(cmd: *CDP.Command) !void {
         .element => {
             // Drivers (e.g. Playwright's click) scroll the target into view and
             // then require its content quads to intersect the viewport.
+            // `params.rect` (Playwright's click position) is ignored: the faux
+            // layout scrolls the whole element into view.
             const frame = bc.mainFrame() orelse return error.FrameNotLoaded;
             const element = node.dom.is(DOMNode.Element).?;
             element.scrollIntoViewIfNeeded(null, element.ownerFrame(frame) orelse frame);