Bug 1437909 [wpt PR 9499] - Correct serialization of background-color, a=testonly

Automatic update from web-platform-testsCorrect serialization of background-color (#9499)

According to https://drafts.csswg.org/css-color/#resolving-color-values, transparent should serialize to "rgba(0, 0, 0, 0)", and named colors should serialize to their equivalent value in rgb notation. Change the expectations for 3 background tests in order to match this part of the spec.

wpt-commits: 43deb07215d283d63e2bdca51d6268eba43bbe81
wpt-pr: 9499
wpt-commits: 43deb07215d283d63e2bdca51d6268eba43bbe81
wpt-pr: 9499

testing/web-platform/meta/MANIFEST.json

@@ -477062,15 +477062,15 @@
    "support"
   ],
   "css/css-backgrounds/background-331.html": [
-   "46a936bd341e7311613693b065c3ac6bcc2c391e",
+   "28185e9f9710a676579fa8de6cc39e1febc9e16f",
    "testharness"
   ],
   "css/css-backgrounds/background-332.html": [
-   "c581a0c1d1dc8f73d035c2b5b960d84516c6a0d9",
+   "ba3453739dee1dac840b3916b09cf161752d2f1d",
    "testharness"
   ],
   "css/css-backgrounds/background-333.html": [
-   "8bf2b28906a57250cbb07665c1be62fd5b4dedab",
+   "42e4208e11dd799e650343b580843b182099a3b2",
    "testharness"
   ],
   "css/css-backgrounds/background-334.html": [

testing/web-platform/tests/css/css-backgrounds/background-331.html

@@ -57,7 +57,7 @@
 
         test(function() {
             assert_equals(cs.getPropertyValue("background-color"),
-                "transparent", "background initial value for background-color");
+                "rgba(0, 0, 0, 0)", "background initial value for background-color");
         }, "background_initial_color");
     </script>
   </body>

testing/web-platform/tests/css/css-backgrounds/background-332.html

@@ -57,7 +57,7 @@
 
         test(function() {
             assert_equals(cs.getPropertyValue("background-color"),
-                "gray", "background specified value for background-color");
+                "rgb(128, 128, 128)", "background specified value for background-color");
         }, "background_specified_color");
     </script>
   </body>

testing/web-platform/tests/css/css-backgrounds/background-333.html

@@ -57,7 +57,7 @@
 
         test(function() {
             assert_equals(cs.getPropertyValue("background-color"),
-                "red", "background specified value for background-color");
+                "rgb(255, 0, 0)", "background specified value for background-color");
         }, "background_specified_color_color");
     </script>
   </body>