Backed out changeset 24043b03134b (bug 1708370) for causing wpt failures at idlharness.https.html

layout/style/res/forms.css

@@ -301,11 +301,6 @@ option[label]::before {
   content: attr(label);
 }
 
-select:-moz-select-list-box option,
-select:-moz-select-list-box optgroup {
-  line-height: normal !important;
-}
-
 option {
   display: block;
   float: none !important;
@@ -315,15 +310,18 @@ option {
 
   min-block-size: 1em;
   padding-block: 2px;
-  user-select: none;
   /*
    * Note that the "UA !important" tests in
    * layout/style/test/test_animations.html depend on this rule, because
    * they need some UA !important rule to test.  If this changes, use a
    * different one there.
    */
+  line-height: normal !important;
+  user-select: none;
+  text-indent: 0;
   white-space: nowrap !important;
   word-wrap: normal !important;
+  text-align: match-parent;
 }
 
 select > option {
@@ -344,10 +342,13 @@ optgroup {
   display: block;
   float: none !important;
   position: static !important;
+  font: -moz-list;
+  line-height: normal !important;
   font-style: italic;
   font-weight: bold;
   font-size: unset;
   user-select: none;
+  text-indent: 0;
   white-space: nowrap !important;
   word-wrap: normal !important;
 }
@@ -360,7 +361,7 @@ optgroup > option {
 
 optgroup:before {
   display: block;
-  content: "\200b" attr(label);
+  content: attr(label);
 }
 
 @media (-moz-platform: android) {
@@ -543,6 +544,7 @@ button,
 ::file-selector-button {
   /* Buttons should lay out like "normal" html, mostly */
   white-space: unset;
+  text-indent: 0;
   /* But no text-decoration reaching inside, by default */
   display: inline-block;
 }

layout/style/test/test_animations.html

@@ -99,7 +99,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=435442
   }
 
   @keyframes uaoverride {
-    0%, 100% { white-space: pre; margin-top: 20px }
+    0%, 100% { line-height: 3; margin-top: 20px }
     50% { margin-top: 120px }
   }
 
@@ -1379,22 +1379,20 @@ done_div();
 
 // Test that UA !important rules override animations.
 // This test depends on forms.css having a rule
-//   option { white-space: !important }
+//   option { line-height: !important }
 // If that rule changes, we should rewrite it to depend on a different rule.
 var option;
 [ option, cs ] = new_element("option", "");
-var default_white_space = cs.whiteSpace;
-isnot(default_white_space, "pre",
-   "default style should not be the same as animation style");
+var default_line_height = cs.lineHeight;
 done_element();
 [ option, cs ] = new_element("option",
                              "animation: uaoverride 2s linear infinite");
-is(cs.whiteSpace, default_white_space,
+is(cs.lineHeight, default_line_height,
    "animations should not override UA !important at 0ms");
 is(cs.marginTop, "20px",
    "rest of animation should still work when UA !important present at 0ms");
 advance_clock(200);
-is(cs.whiteSpace, default_white_space,
+is(cs.lineHeight, default_line_height,
    "animations should not override UA !important at 200ms");
 is(cs.marginTop, "40px",
    "rest of animation should still work when UA !important present at 200ms");

testing/web-platform/meta/html/rendering/non-replaced-elements/form-controls/resets.html.ini

@@ -0,0 +1,17 @@
+[resets.html]
+  expected:
+    if (os == "android") and fission: [TIMEOUT, OK]
+  [<optgroup> - text-indent]
+    expected: FAIL
+
+  [<option> - line-height]
+    expected: FAIL
+
+  [<option> - text-indent]
+    expected: FAIL
+
+  [<optgroup> - line-height]
+    expected: FAIL
+
+  [<option> (in <select><optgroup>) - text-align]
+    expected: FAIL