Forced accent-color followup

In CL:2847031, accent-color was forced to auto in forced colors mode.
This CL moves this logic to StyleAdjuster::AdjustForForcedColorsMode()
so that it is forced in the same place as the other properties forced
at computed value time.

Bug: 1092093
Change-Id: I77ba92e30c6ea060521a8d05747c32a38f149601
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2909975
Reviewed-by: Joey Arhar <jarhar@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Commit-Queue: Alison Maher <almaher@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#886369}
diff --git a/forced-colors-mode/forced-colors-mode-50.html b/forced-colors-mode/forced-colors-mode-50.html
new file mode 100644
index 0000000..5a98534
--- /dev/null
+++ b/forced-colors-mode/forced-colors-mode-50.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Forced colors mode - accent-color.</title>
+<link rel="help" href="https://www.w3.org/TR/css-color-adjust-1/#forced-colors-properties">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  input {
+    accent-color: green;
+  }
+  #a {
+    forced-color-adjust: none;
+  }
+</style>
+<input type="checkbox" id="a" checked>
+<input type="checkbox" id="b" checked>
+
+<script>
+  test(function(){
+    assert_equals(getComputedStyle(a).accentColor, "rgb(0, 128, 0)");
+    assert_equals(getComputedStyle(b).accentColor, "auto");
+  }, "Accent-color computes to auto in forced colors mode, unless forced-color-adjust is none.");
+</script>