Highlight logic incorrect for checking author set text color

https://bugs.webkit.org/show_bug.cgi?id=258943
rdar://111706100

Reviewed by Megan Gardner and Aditya Keerthi.

Before logic to determine whether to take a text color of a
StyledMarkedText was to compare to canvasText color.
This causes aproblem if author set color to canvasText or if the color
black was considered as canvasText.
Now, we check if a flag was set indicating the author explicitly
specified a text color.
Updated TestExpectations due to passing test.
Part of priority in spec: https://www.w3.org/TR/css-highlight-api-1/#priorities

* LayoutTests/TestExpectations:
* Source/WebCore/rendering/StyledMarkedText.cpp:
(WebCore::resolveStyleForMarkedText):
(WebCore::coalesceAdjacentWithSameRanges):
* Source/WebCore/rendering/TextPaintStyle.cpp:
(WebCore::computeTextSelectionPaintStyle):
* Source/WebCore/rendering/TextPaintStyle.h:

Canonical link: https://commits.webkit.org/266117@main

LayoutTests/TestExpectations

@@ -4905,7 +4905,6 @@ imported/w3c/web-platform-tests/css/css-highlight-api/painting/custom-highlight-
 imported/w3c/web-platform-tests/css/css-highlight-api/painting/custom-highlight-painting-inheritance-002.html [ ImageOnlyFailure ]
 imported/w3c/web-platform-tests/css/css-highlight-api/painting/custom-highlight-painting-invalidation-003.html [ ImageOnlyFailure ]
 imported/w3c/web-platform-tests/css/css-highlight-api/painting/custom-highlight-painting-invalidation-006.html [ ImageOnlyFailure ]
-imported/w3c/web-platform-tests/css/css-highlight-api/painting/custom-highlight-painting-017.html [ ImageOnlyFailure ]
 
 http/tests/webgl/1.0.x/conformance/textures/misc/origin-clean-conformance-offscreencanvas.html [ Skip ]
 http/tests/webgl/2.0.y/conformance/textures/misc/origin-clean-conformance-offscreencanvas.html [ Skip ]

Source/WebCore/rendering/StyledMarkedText.cpp

@@ -54,6 +54,7 @@ static StyledMarkedText resolveStyleForMarkedText(const MarkedText& markedText,
             style.backgroundColor = renderStyle->colorResolvingCurrentColor(renderStyle->backgroundColor());
             style.textStyles.fillColor = renderStyle->computedStrokeColor();
             style.textStyles.strokeColor = renderStyle->computedStrokeColor();
+            style.textStyles.hasExplicitlySetFillColor = renderStyle->hasExplicitlySetColor();
 
             auto color = TextDecorationPainter::decorationColor(*renderStyle.get());
             auto decorationStyle = renderStyle->textDecorationStyle();
@@ -136,9 +137,8 @@ static Vector<StyledMarkedText> coalesceAdjacentWithSameRanges(Vector<StyledMark
                     || !it->style.backgroundColor.isOpaque()
                     || (it->highlightName.isNull() && it->style.backgroundColor.isVisible())))
                         previousStyledMarkedText.style.backgroundColor = blendSourceOver(previousStyledMarkedText.style.backgroundColor, it->style.backgroundColor);
-            // Take text color of the StyledMarkedText that has set it, maintaining insertion order.
-            // FIXME: Case of user setting color to CanvasText, will not choose CanvasText as prioritized color to paint.
-            if (it->type != MarkedText::Type::Unmarked && it->style.textStyles.fillColor != RenderTheme::singleton().systemColor(CSSValueCanvastext, { }))
+            // Take text color of StyledMarkedText, maintaining insertion and priority order.
+            if (it->type != MarkedText::Type::Unmarked && it->style.textStyles.hasExplicitlySetFillColor)
                 previousStyledMarkedText.style.textStyles.fillColor = it->style.textStyles.fillColor;
             // Take the highlightName of the latest StyledMarkedText, regardless of priority.
             if (!it->highlightName.isNull())

Source/WebCore/rendering/TextPaintStyle.cpp

@@ -149,6 +149,7 @@ TextPaintStyle computeTextSelectionPaintStyle(const TextPaintStyle& textPaintSty
         selectionPaintStyle.emphasisMarkColor = emphasisMarkForeground;
 
     if (auto pseudoStyle = renderer.selectionPseudoStyle()) {
+        selectionPaintStyle.hasExplicitlySetFillColor = pseudoStyle->hasExplicitlySetColor();
         selectionShadow = ShadowData::clone(paintInfo.forceTextColor() ? nullptr : pseudoStyle->textShadow());
         auto viewportSize = renderer.frame().view() ? renderer.frame().view()->size() : IntSize();
         float strokeWidth = pseudoStyle->computedStrokeWidth(viewportSize);

Source/WebCore/rendering/TextPaintStyle.h

@@ -48,6 +48,8 @@ struct TextPaintStyle {
     Color strokeColor;
     Color emphasisMarkColor;
     float strokeWidth { 0 };
+    // This is not set for -webkit-text-fill-color.
+    bool hasExplicitlySetFillColor { false };
 #if HAVE(OS_DARK_MODE_SUPPORT)
     bool useDarkAppearance { false };
 #endif