Update spelling|grammar error markers rendering on Mac

Mac platform used to have a gradient on spelling|grammar error markers,
but that's no longer the case anymore.
This patch removes such gradient and also updates the colors
so they match the ones used by WebKit on Mac.

Change-Id: Ia6cd75a0c70f6ea4884493f6b8e69de48bf92b4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3139819
Reviewed-by: Philip Rogers <[email protected]>
Reviewed-by: Avi Drissman <[email protected]>
Commit-Queue: Manuel Rego <[email protected]>
Cr-Commit-Position: refs/heads/main@{#918855}

Author: mrego

third_party/blink/renderer/core/layout/layout_theme_mac.mm

@@ -72,11 +72,15 @@ Color GetSystemColor(MacSystemColorID color_id,
 }
 
 Color LayoutThemeMac::PlatformSpellingMarkerUnderlineColor() const {
-  return Color(251, 45, 29);
+  // Using the same color than WebKit (see
+  // https://github.com/WebKit/WebKit/blob/main/Source/WebCore/platform/graphics/cocoa/GraphicsContextCocoa.mm#L167).
+  return Color(255, 59, 48, 191);
 }
 
 Color LayoutThemeMac::PlatformGrammarMarkerUnderlineColor() const {
-  return Color(107, 107, 107);
+  // Using the same color than WebKit (see
+  // https://github.com/WebKit/WebKit/blob/main/Source/WebCore/platform/graphics/cocoa/GraphicsContextCocoa.mm#L175).
+  return Color(25, 175, 50, 191);
 }
 
 bool LayoutThemeMac::IsAccentColorCustomized(

third_party/blink/renderer/core/paint/document_marker_painter.cc

@@ -75,18 +75,9 @@ sk_sp<PaintRecord> RecordMarker(Color blink_color) {
   // Match the artwork used by the Mac.
   static const float kR = 1.5f;
 
-  // top->bottom translucent gradient.
-  const SkColor colors[2] = {
-      SkColorSetARGB(0x48, SkColorGetR(color), SkColorGetG(color),
-                     SkColorGetB(color)),
-      color};
-  const SkPoint pts[2] = {SkPoint::Make(0, 0), SkPoint::Make(0, 2 * kR)};
-
   PaintFlags flags;
   flags.setAntiAlias(true);
   flags.setColor(color);
-  flags.setShader(PaintShader::MakeLinearGradient(
-      pts, colors, nullptr, base::size(colors), SkTileMode::kClamp));
   PaintRecorder recorder;
   recorder.beginRecording(kMarkerWidth, kMarkerHeight);
   recorder.getRecordingCanvas()->drawOval(SkRect::MakeWH(2 * kR, 2 * kR),