Change omnibox background color from push-toward-dark to push-toward-nearest.

Bug: 1042807
Change-Id: I9f8554970d5344bf9c90ced78aa925e8fa77282b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2023276Reviewed-by: Evan Stade <estade@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735649}

chrome/browser/themes/theme_service.cc

@@ -623,12 +623,13 @@ SkColor ThemeService::GetDefaultColor(int id, bool incognito) const {
     case TP::COLOR_OMNIBOX_BACKGROUND: {
       constexpr float kMinOmniboxToolbarContrast = 1.3f;
       const SkColor toolbar_color = GetColor(TP::COLOR_TOOLBAR, incognito);
-      const SkColor darkest_color = color_utils::GetDarkestColor();
+      const SkColor endpoint_color =
+          color_utils::GetEndpointColorWithMinContrast(toolbar_color);
       const SkColor blend_target =
-          (color_utils::GetContrastRatio(toolbar_color, darkest_color) >=
+          (color_utils::GetContrastRatio(toolbar_color, endpoint_color) >=
            kMinOmniboxToolbarContrast)
-              ? darkest_color
-              : color_utils::GetColorWithMaxContrast(darkest_color);
+              ? endpoint_color
+              : color_utils::GetColorWithMaxContrast(endpoint_color);
       return color_utils::BlendForMinContrast(toolbar_color, toolbar_color,
                                               blend_target,
                                               kMinOmniboxToolbarContrast)

chrome/browser/ui/color/chrome_color_mixers.cc

@@ -19,11 +19,12 @@ ui::ColorTransform ChooseOmniboxBgBlendTarget() {
   return base::BindRepeating(
       [](SkColor input_color, const ui::ColorMixer& mixer) {
         const SkColor toolbar_color = mixer.GetResultColor(kColorToolbar);
-        const SkColor darkest_color = color_utils::GetDarkestColor();
-        return (color_utils::GetContrastRatio(toolbar_color, darkest_color) >=
+        const SkColor endpoint_color =
+            color_utils::GetEndpointColorWithMinContrast(toolbar_color);
+        return (color_utils::GetContrastRatio(toolbar_color, endpoint_color) >=
                 kMinOmniboxToolbarContrast)
-                   ? darkest_color
-                   : color_utils::GetColorWithMaxContrast(darkest_color);
+                   ? endpoint_color
+                   : color_utils::GetColorWithMaxContrast(endpoint_color);
       });
 }
 

ui/color/color_transform.cc

@@ -106,7 +106,7 @@ ColorTransform ContrastInvert(ColorTransform transform) {
     const SkColor far_endpoint =
         color_utils::GetColorWithMaxContrast(foreground);
     const SkColor near_endpoint =
-        color_utils::GetColorWithMaxContrast(far_endpoint);
+        color_utils::GetEndpointColorWithMinContrast(foreground);
     const float contrast_ratio =
         color_utils::GetContrastRatio(foreground, far_endpoint);
     return color_utils::BlendForMinContrast(foreground, near_endpoint,

ui/gfx/color_utils.cc

@@ -306,6 +306,10 @@ SkColor GetColorWithMaxContrast(SkColor color) {
   return IsDark(color) ? SK_ColorWHITE : g_darkest_color;
 }
 
+SkColor GetEndpointColorWithMinContrast(SkColor color) {
+  return IsDark(color) ? g_darkest_color : SK_ColorWHITE;
+}
+
 SkColor BlendTowardMaxContrast(SkColor color, SkAlpha alpha) {
   SkAlpha original_alpha = SkColorGetA(color);
   SkColor blended_color = AlphaBlend(GetColorWithMaxContrast(color),
@@ -400,10 +404,6 @@ std::string SkColorToRgbString(SkColor color) {
                             SkColorGetB(color));
 }
 
-SkColor GetDarkestColor() {
-  return g_darkest_color;
-}
-
 SkColor SetDarkestColorForTesting(SkColor color) {
   const SkColor previous_darkest_color = g_darkest_color;
   g_darkest_color = color;

ui/gfx/color_utils.h

@@ -127,6 +127,10 @@ GFX_EXPORT bool IsDark(SkColor color);
 // |color|.
 GFX_EXPORT SkColor GetColorWithMaxContrast(SkColor color);
 
+// Returns whichever of white or the darkest available color contrasts less with
+// |color|.
+GFX_EXPORT SkColor GetEndpointColorWithMinContrast(SkColor color);
+
 // Blends towards the color with max contrast by |alpha|. The alpha of
 // the original color is preserved.
 GFX_EXPORT SkColor BlendTowardMaxContrast(SkColor color, SkAlpha alpha);
@@ -171,9 +175,6 @@ GFX_EXPORT std::string SkColorToRgbaString(SkColor color);
 // Creates an rgb string for an SkColor. For example: '255,0,255'.
 GFX_EXPORT std::string SkColorToRgbString(SkColor color);
 
-// Returns the darkest available color.
-GFX_EXPORT SkColor GetDarkestColor();
-
 // Sets the darkest available color to |color|.  Returns the previous darkest
 // color.
 GFX_EXPORT SkColor SetDarkestColorForTesting(SkColor color);

ui/gfx/color_utils_unittest.cc

@@ -205,14 +205,6 @@ TEST(ColorUtils, SkColorToRgbString) {
   EXPECT_EQ(color_string, "50,100,150");
 }
 
-TEST(ColorUtils, GetAndSetDarkestColor) {
-  const SkColor old_darkest_color = GetDarkestColor();
-  EXPECT_EQ(old_darkest_color, SetDarkestColorForTesting(SK_ColorLTGRAY));
-  EXPECT_EQ(SK_ColorLTGRAY, GetDarkestColor());
-  EXPECT_EQ(SK_ColorLTGRAY, SetDarkestColorForTesting(old_darkest_color));
-  EXPECT_EQ(old_darkest_color, GetDarkestColor());
-}
-
 TEST(ColorUtils, IsDarkDarkestColorChange) {
   ASSERT_FALSE(IsDark(SK_ColorLTGRAY));
   const SkColor old_darkest_color = SetDarkestColorForTesting(SK_ColorLTGRAY);
@@ -247,6 +239,20 @@ TEST(ColorUtils, GetColorWithMaxContrast) {
   EXPECT_EQ(old_darkest_color, GetColorWithMaxContrast(SK_ColorWHITE));
 }
 
+TEST(ColorUtils, GetEndpointColorWithMinContrast) {
+  const SkColor old_darkest_color = SetDarkestColorForTesting(SK_ColorBLACK);
+  EXPECT_EQ(SK_ColorBLACK, GetEndpointColorWithMinContrast(SK_ColorBLACK));
+  EXPECT_EQ(SK_ColorBLACK,
+            GetEndpointColorWithMinContrast(SkColorSetRGB(0x75, 0x75, 0x75)));
+  EXPECT_EQ(SK_ColorWHITE, GetEndpointColorWithMinContrast(SK_ColorWHITE));
+  EXPECT_EQ(SK_ColorWHITE,
+            GetEndpointColorWithMinContrast(SkColorSetRGB(0x76, 0x76, 0x76)));
+
+  SetDarkestColorForTesting(old_darkest_color);
+  EXPECT_EQ(old_darkest_color,
+            GetEndpointColorWithMinContrast(old_darkest_color));
+}
+
 TEST(ColorUtils, BlendForMinContrast_ForegroundAlreadyMeetsMinimum) {
   const auto result = BlendForMinContrast(SK_ColorBLACK, SK_ColorWHITE);
   EXPECT_EQ(SK_AlphaTRANSPARENT, result.alpha);