GMC: Update minimum contrast ratio

This CL updates the Global Media Controls dialog to use 7 as the
minimum contrast ratio between the foreground and background colors
instead of using the default of 4.5.

Bug: 1049242
Change-Id: I81538040993cdd555cd1e6173554b9021018d18e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2039894
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738688}

components/media_message_center/media_notification_background.cc

@@ -35,6 +35,8 @@ constexpr double kMediaNotificationForegroundColorMostPopularMinSaturation =
 // The ratio for the more vibrant foreground color to use.
 constexpr double kMediaNotificationForegroundColorMoreVibrantRatio = 1.0;
 
+constexpr float kMediaNotificationMinimumContrastRatio = 7.0;
+
 bool IsNearlyWhiteOrBlack(SkColor color) {
   color_utils::HSL hsl;
   color_utils::SkColorToHSL(color, &hsl);
@@ -356,7 +358,9 @@ SkColor MediaNotificationBackground::GetForegroundColor(
           ? *foreground_color_
           : views::style::GetColor(owner, views::style::CONTEXT_LABEL,
                                    views::style::STYLE_PRIMARY);
-  return color_utils::BlendForMinContrast(foreground, GetBackgroundColor(owner))
+  return color_utils::BlendForMinContrast(
+             foreground, GetBackgroundColor(owner), base::nullopt,
+             kMediaNotificationMinimumContrastRatio)
       .color;
 }
 

components/media_message_center/media_notification_view_impl_unittest.cc

@@ -817,7 +817,7 @@ TEST_F(MAYBE_MediaNotificationViewImplTest, UpdateArtworkFromItem) {
 
   SkBitmap image;
   image.allocN32Pixels(10, 10);
-  image.eraseColor(SK_ColorMAGENTA);
+  image.eraseColor(SK_ColorGREEN);
 
   EXPECT_TRUE(GetArtworkImage().isNull());