Bug 1678010 [wpt PR 26561] - [CSS] Return empty string for CSSStyleDe…

…claration.cssText, a=testonly

Automatic update from web-platform-tests
[CSS] Return empty string for CSSStyleDeclaration.cssText

This patch changes the code to return empty string for
CSSStyleDeclaration.cssText.

Discussion at:
w3c/csswg-drafts#1033

Makes tests pass:
external/wpt/css/cssom/cssstyledeclaration-csstext.html

Bug: 1146888
Change-Id: Ibca415b7606d2cc5110ca633c87a77fac3e74ca8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2546305
Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Jaeyong Bae <jdragon.bae@gmail.com>
Cr-Commit-Position: refs/heads/master@{#829173}

--

wpt-commits: 37a7ebd1a46e1bca71f1cda94922b681555519a3
wpt-pr: 26561

testing/web-platform/tests/scroll-animations/css/animation-timeline-computed.html

@@ -39,7 +39,7 @@
 }, 'The animation-timeline property shows up in CSSStyleDeclaration enumeration');
 
 test(() => {
-  let style = getComputedStyle(document.getElementById('target'));
+  let style = document.getElementById('target').style;
   assert_not_equals(style.cssText.indexOf('animation-timeline'), -1);
 }, 'The animation-timeline property shows up in CSSStyleDeclaration.cssText');
 </script>