Update the name of forced-colors in UA stylesheets

This change updates the name of the forced-colors media query within
the UA stylesheets to ua-forced-colors. This is done to make it clear
that it is a UA-specific hack for forced-colors.

This is based on feedback from
https://chromium-review.googlesource.com/c/chromium/src/+/2211124.

Bug: 970285
Change-Id: Ic99620f7886a82cfbb87d929bf7f985f474714c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2227098Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Alison Maher <almaher@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#774663}

third_party/blink/renderer/core/css/css_default_style_sheets.cc

@@ -67,9 +67,11 @@ static const MediaQueryEvaluator& PrintEval() {
 }
 
 static const MediaQueryEvaluator& ForcedColorsEval() {
+  // We use "ua-forced-colors" here instead of "forced-colors" to indicate that
+  // this is a UA hack for the "forced-colors" media query.
   DEFINE_STATIC_LOCAL(
       Persistent<MediaQueryEvaluator>, forced_colors_eval,
-      (MakeGarbageCollected<MediaQueryEvaluator>("forced-colors")));
+      (MakeGarbageCollected<MediaQueryEvaluator>("ua-forced-colors")));
   return *forced_colors_eval;
 }
 

third_party/blink/renderer/core/css/svg.css

@@ -94,7 +94,7 @@ foreignObject {
    This is added as to not break SVG content in forced colors mode:
    https://drafts.csswg.org/css-color-adjust-1/#forced-colors-properties
 */
-@media forced-colors {
+@media ua-forced-colors {
   svg:root {
     color: CanvasText;
   }

third_party/blink/renderer/core/html/resources/forced_colors.css

@@ -14,7 +14,7 @@
    @namespace "http://www.w3.org/1999/xhtml"
 */
 
-@media forced-colors {
+@media ua-forced-colors {
   html {
     color: CanvasText;
     fill: currentColor;