Let Node::ParentComputedStyle return nullptr for Document

andruud · chromium-wpt-export-bot · commit f781a1c2bd9b · 2021-09-23T05:34:05.000-07:00
During Element::RecalcOwnStyle, we call ParentComputedStyle(), which currently returns a non-nullptr ComputedStyle on the document element. This suggests that we will or should inherit from that style, and that is not right. Later in the style resolution process, we *do* correctly use nullptr in most cases [1], but for the new highlight code we set the parent override to ParentComputedStyle()'s result directly, causing problems. This CL: - Returns nullptr from ParentComputedStyle() if the parent is not an Element. - Moves ParentComputedStyle() to Element. - Allows pseudo-style-resolves without a parent override, since this is the correct thing to do for the new highlight pseudo behavior. - Fixes a bug where initial custom property values would not be available in :root::selection (etc). This is because those values are set up in InitialStyleForElement, and the highlight inheritance chain never used that function until now. Note that there is a still an initial-value bug for ::selection (etc) on non-:root, but a fix for that will come later. [1] ElementResolveContext::ParentStyle, which checks for IsElementNode Bug: 1024156 Change-Id: I3f0f2c1841cbe3e7ffeedb3a295b6f470957efc7 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3173223 Reviewed-by: Rune Lillesveen <futhark@chromium.org> Reviewed-by: Delan Azabani <dazabani@igalia.com> Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org> Cr-Commit-Position: refs/heads/main@{#924262}
diff --git a/css/css-pseudo/highlight-cascade-003-ref.html b/css/css-pseudo/highlight-cascade-003-ref.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<title>Initial custom property values in :root::selection rule</title>
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#highlight-cascade">
+<script src="support/selections.js"></script>
+<style>
+  :root::selection {
+    background-color: green;
+  }
+</style>
+<main>PASS if background-color is green when selected</main>
+<script>
+  selectNodeContents(document.querySelector("main"));
+</script>
diff --git a/css/css-pseudo/highlight-cascade-003.html b/css/css-pseudo/highlight-cascade-003.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<title>Initial custom property values in :root::selection rule</title>
+<link rel="help" href="https://drafts.csswg.org/css-pseudo-4/#highlight-cascade">
+<link rel="match" href="highlight-cascade-003-ref.html">
+<meta name="assert" value="This test verifies that the initial value given in a custom property registration is respected, when the property is referenced in ::selection styles but no value is defined. The initial value is not the guaranteed-invalid value, so the fallback value in var() is not used.">
+<script src="support/selections.js"></script>
+<style>
+  @property --bg {
+    syntax: "<color>";
+    inherits: false;
+    initial-value: green;
+  }
+  :root::selection {
+    background-color: var(--bg, red);
+  }
+</style>
+<main>PASS if background-color is green when selected</main>
+<script>
+  selectNodeContents(document.querySelector("main"));
+</script>
