Hoist StyleNew{Children,Subtree} into their own paths.

The buggy animation handling isn't a regression, since currently we pass
UnstyledChildrenOnly in those cases, which blocks the animation traversal
in Servo_TraverseSubtree.

In general I really wanted to handle these two paths together. But there's
enough broken with the NewChildren path that I wanted to scope the buginess
as tightly as possible. And I really need to separate the handling here from
StyleDocument() to make the restyle root stuff work.

MozReview-Commit-ID: 9F0mcQl7AAX

1 files changed, 4 insertions, 3 deletions

diff --git a/components/style/traversal_flags.rs b/components/style/traversal_flags.rs
index a2e0cdc7515..7a985c3d3cf 100644
--- a/components/style/traversal_flags.rs
+++ b/components/style/traversal_flags.rs
@@ -16,8 +16,9 @@ bitflags! {
         /// Traverse and update all elements with CSS animations since
         /// @keyframes rules may have changed. Triggered by CSS rule changes.
         const ForCSSRuleChanges = 1 << 1,
-        /// Traverse only unstyled children of the root and their descendants.
-        const UnstyledChildrenOnly = 1 << 2,
+        /// Styles unstyled elements, but does not handle invalidations on
+        /// already-styled elements.
+        const UnstyledOnly = 1 << 2,
         /// A forgetful traversal ignores the previous state of the frame tree, and
         /// thus does not compute damage or maintain other state describing the styles
         /// pre-traversal. A forgetful traversal is usually the right thing if you
@@ -55,7 +56,7 @@ pub fn assert_traversal_flags_match() {
     check_traversal_flags! {
         ServoTraversalFlags_AnimationOnly => AnimationOnly,
         ServoTraversalFlags_ForCSSRuleChanges => ForCSSRuleChanges,
-        ServoTraversalFlags_UnstyledChildrenOnly => UnstyledChildrenOnly,
+        ServoTraversalFlags_UnstyledOnly => UnstyledOnly,
         ServoTraversalFlags_Forgetful => Forgetful,
         ServoTraversalFlags_AggressivelyForgetful => AggressivelyForgetful,
         ServoTraversalFlags_ClearDirtyDescendants => ClearDirtyDescendants,