third_party/WebKit/LayoutTests/fast/selectors/style-sharing-children-prevent-sharing.html

   1 <!DOCTYPE html>
   2 <script src="../../resources/js-test.js"></script>
   3 <style>
   4 .root + #lastChildRules {
   5     color: red;
   6 }
   7 </style>
   8
   9 <div id="y" class="root">
  10     <div></div>
  11 </div>
  12
  13 <div id="x" class="root">
  14     <div></div>
  15 </div>
  16
  17 <script>
  18 description("Test dynamic changes to the childrenSupportStyleSharing flag.");
  19
  20 var x = document.getElementById("x");
  21 var y = document.getElementById("y");
  22
  23 // Attach the whole tree, this makes x and y share, and the children of x and y share.
  24 document.body.offsetTop;
  25
  26 // Add a child that make us match sibling rules. This will set the ChildrenAffectedByDirectAdjacentRules
  27 // flag on #x preventing its children from sharing in the future.
  28 var lastChildRules = x.appendChild(document.createElement("div"));
  29 lastChildRules.id = "lastChildRules";
  30 x.appendChild(document.createElement("div"));
  31
  32 // Add a new child to #y. Normally it could share with children of #x since both #x and #y share,
  33 // but now #x has children affected by RestyleFlags so they can no longer share.
  34 // FIXME: This element could technically share with the other <div> inside #y, but recalcStyle
  35 // goes from lastChild -> firstChild so we haven't added the firstChild (which doesn't need a recalc)
  36 // to the candidate list yet.
  37 y.appendChild(document.createElement("div"));
  38
  39 document.body.offsetTop;
  40
  41 if (window.internals) {
  42     shouldBeTrue("internals.isSharingStyle(x, y)");
  43     shouldBeTrue("internals.isSharingStyle(x.firstElementChild, y.firstElementChild)");
  44     shouldBeFalse("internals.isSharingStyle(x.firstElementChild, y.firstElementChild.nextElementSibling)");
  45     shouldBeFalse("internals.isSharingStyle(lastChildRules, x.firstElementChild)");
  46     shouldBeFalse("internals.isSharingStyle(lastChildRules, y.firstElementChild)");
  47
  48     // FIXME: We should see if we can look at direct siblings somehow since these elements do
  49     // match the same rules at the same depth, recalcStyle is just in the wrong order to allow
  50     // them to share.
  51     shouldBeFalse("internals.isSharingStyle(y.firstElementChild, y.firstElementChild.nextElementSibling)");
  52 }
  53 </script>