Bug 1864470 [wpt PR 43117] - Avoid spec ambiguity in scroll-target-sn…

…ap-* tests., a=testonly

Automatic update from web-platform-tests
Avoid spec ambiguity in scroll-target-snap-* tests.

Chrome prioritizes ScrollIntoViewOptions over scroll-snap-align, but the
specs need clarification on this point:

w3c/csswg-drafts#9576

In the meantime, have the tests use scroll-snap-align: start instead of
center, so that it matches the default ScrollIntoViewOptions.

Bug: 1325845
Change-Id: Ibd40a187cc86b9286ff9e2c7a67ed59d7233185b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5025233
Reviewed-by: Robert Flack <flackrchromium.org>
Commit-Queue: Steve Kobes <skobeschromium.org>
Cr-Commit-Position: refs/heads/main{#1223689}

--

wpt-commits: ff3d3e29464e87581edc6eea7037485e424097d7
wpt-pr: 43117

UltraBlame original commit: e0272cfd4f73823e45cff178a76e6e89e379c848

testing/web-platform/tests/css/css-scroll-snap/scroll-target-snap-002.html

@@ -25,8 +25,12 @@
   .container > div {
     height: 1em;
   }
-  #target    { scroll-margin:    1em 0 0;
-               scroll-snap-align: center; } /* set up a snap position      */
+  /* Note: we use "start" for #target to avoid spec ambiguity where
+   * scroll-snap-align conflicts with default ScrollIntoViewOptions.
+   * See https://github.com/w3c/csswg-drafts/issues/9576.
+   */
+  #target    { scroll-margin:    2em 0 0;
+               scroll-snap-align: start;  } /* set up a snap position      */
   #stripe    { background: green;         } /* color part of the snap area */
   .fail      { color: red;                } /* make failing more obvious   */
 

testing/web-platform/tests/css/css-scroll-snap/support/scroll-target-snap-001-iframe.html

@@ -17,8 +17,12 @@
   div {
     height: 1em;
   }
-  #target { scroll-margin:     1em 0 0;
-            scroll-snap-align:  center; } /* set up a snap position      */
+  /* Note: we use "start" for #target to avoid spec ambiguity where
+   * scroll-snap-align conflicts with default ScrollIntoViewOptions.
+   * See https://github.com/w3c/csswg-drafts/issues/9576.
+   */
+  #target { scroll-margin:     2em 0 0;
+            scroll-snap-align:  start;  } /* set up a snap position      */
   #stripe { background: green;          } /* color part of the snap area */
   .fail   { color: red;                 } /* make failing more obvious   */