Ensure omnibox foreground colors are readable over hovered backgrounds

R=pkasting
BUG=None

Change-Id: Ife6d481a840fc23b7aac527de332e4185d744ed8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1822841
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699472}

chrome/browser/themes/theme_service.cc

@@ -1181,8 +1181,12 @@ base::Optional<SkColor> ThemeService::GetOmniboxColor(
   const bool dark = IsDark(bg.value);
 
   auto results_bg_color = [&]() { return get_color_with_max_contrast(fg); };
+  auto bg_hovered_color = [&]() { return blend_toward_max_contrast(bg, 0x0A); };
   auto security_chip_color = [&](OmniboxColor color) {
-    return blend_for_min_contrast(color, bg);
+    return blend_for_min_contrast(color, bg_hovered_color());
+  };
+  auto results_bg_hovered_color = [&]() {
+    return blend_toward_max_contrast(results_bg_color(), 0x1A);
   };
   auto url_color = [&](OmniboxColor bg) {
     return blend_for_min_contrast(
@@ -1204,7 +1208,7 @@ base::Optional<SkColor> ThemeService::GetOmniboxColor(
       case TP::COLOR_OMNIBOX_BACKGROUND:
         return bg;
       case TP::COLOR_OMNIBOX_BACKGROUND_HOVERED:
-        return blend_toward_max_contrast(bg, 0x0A);
+        return bg_hovered_color();
       case TP::COLOR_OMNIBOX_RESULTS_BG:
         return results_bg_color();
       case TP::COLOR_OMNIBOX_RESULTS_BG_SELECTED:
@@ -1220,9 +1224,9 @@ base::Optional<SkColor> ThemeService::GetOmniboxColor(
       case TP::COLOR_OMNIBOX_BUBBLE_OUTLINE_EXPERIMENTAL_KEYWORD_MODE:
         return url_color(results_bg_color());
       case TP::COLOR_OMNIBOX_TEXT_DIMMED:
-        return blend_with_clamped_contrast(bg);
+        return blend_with_clamped_contrast(bg_hovered_color());
       case TP::COLOR_OMNIBOX_RESULTS_TEXT_DIMMED:
-        return blend_with_clamped_contrast(results_bg_color());
+        return blend_with_clamped_contrast(results_bg_hovered_color());
       case TP::COLOR_OMNIBOX_RESULTS_TEXT_DIMMED_SELECTED:
         return blend_with_clamped_contrast(results_bg_selected_color());
       case TP::COLOR_OMNIBOX_RESULTS_ICON:
@@ -1232,9 +1236,9 @@ base::Optional<SkColor> ThemeService::GetOmniboxColor(
         return blend_for_min_contrast(derive_default_icon_color(fg),
                                       results_bg_selected_color());
       case TP::COLOR_OMNIBOX_RESULTS_BG_HOVERED:
-        return blend_toward_max_contrast(results_bg_color(), 0x1A);
+        return results_bg_hovered_color();
       case TP::COLOR_OMNIBOX_RESULTS_URL:
-        return url_color(results_bg_color());
+        return url_color(results_bg_hovered_color());
       case TP::COLOR_OMNIBOX_RESULTS_URL_SELECTED:
         return url_color(results_bg_selected_color());
       case TP::COLOR_OMNIBOX_SECURITY_CHIP_DEFAULT:

chrome/browser/themes/theme_service_unittest.cc

@@ -586,19 +586,12 @@ TEST_F(ThemeServiceTest, OmniboxContrast) {
            TP::COLOR_OMNIBOX_BACKGROUND},
           {TP::COLOR_OMNIBOX_SECURITY_CHIP_DANGEROUS,
            TP::COLOR_OMNIBOX_RESULTS_BG},
-          // TODO(thomasanderson): Because colors are computed relative to
-          // non-hovered backgrounds, some colors over hovered backgrounds do
-          // not have sufficient contrast in all configurations.  Computing the
-          // non-contrasty colors here relative to hovered backgrounds should
-          // fix this and not reduce contrast of non-hovered backgrounds.
-          // {TP::COLOR_OMNIBOX_TEXT_DIMMED,
-          //  TP::COLOR_OMNIBOX_BACKGROUND_HOVERED},
-          // {TP::COLOR_OMNIBOX_RESULTS_TEXT_DIMMED,
-          //  TP::COLOR_OMNIBOX_RESULTS_BG_HOVERED},
-          // {TP::COLOR_OMNIBOX_RESULTS_URL,
-          //  TP::COLOR_OMNIBOX_RESULTS_BG_HOVERED},
-          // {TP::COLOR_OMNIBOX_SECURITY_CHIP_DANGEROUS,
-          //  TP::COLOR_OMNIBOX_BACKGROUND_HOVERED},
+          {TP::COLOR_OMNIBOX_TEXT_DIMMED, TP::COLOR_OMNIBOX_BACKGROUND_HOVERED},
+          {TP::COLOR_OMNIBOX_RESULTS_TEXT_DIMMED,
+           TP::COLOR_OMNIBOX_RESULTS_BG_HOVERED},
+          {TP::COLOR_OMNIBOX_RESULTS_URL, TP::COLOR_OMNIBOX_RESULTS_BG_HOVERED},
+          {TP::COLOR_OMNIBOX_SECURITY_CHIP_DANGEROUS,
+           TP::COLOR_OMNIBOX_BACKGROUND_HOVERED},
       };
       auto check_sufficient_contrast = [&](int id1, int id2) {
         const float contrast = color_utils::GetContrastRatio(