Remove support for (prefers-color-scheme: no-preference).

The 'no-preference' value was removed from the spec per CSSWG
resolution.

Intent to ship:

https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/ragu5Is6vCw

Bug: 1091806
Change-Id: I6410f99badd26ad18fddadf014115dd754ca6aec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2232922Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Tobias Sargeant <tobiasjs@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776895}

android_webview/browser/aw_settings.cc

@@ -529,14 +529,13 @@ void AwSettings::PopulateWebPreferencesLocked(JNIEnv* env,
       break;
     }
   }
-  web_prefs->preferred_color_scheme =
-      is_dark_mode ? blink::PreferredColorScheme::kDark
-                   : blink::PreferredColorScheme::kNoPreference;
+  web_prefs->preferred_color_scheme = is_dark_mode
+                                          ? blink::PreferredColorScheme::kDark
+                                          : blink::PreferredColorScheme::kLight;
   if (is_dark_mode) {
     switch (Java_AwSettings_getForceDarkBehaviorLocked(env, obj)) {
       case ForceDarkBehavior::FORCE_DARK_ONLY: {
-        web_prefs->preferred_color_scheme =
-            blink::PreferredColorScheme::kNoPreference;
+        web_prefs->preferred_color_scheme = blink::PreferredColorScheme::kLight;
         web_prefs->force_dark_mode_enabled = true;
         break;
       }
@@ -547,7 +546,7 @@ void AwSettings::PopulateWebPreferencesLocked(JNIEnv* env,
       }
       // Blink's behavior is that if the preferred color scheme matches the
       // supported color scheme, then force dark will be disabled, otherwise
-      // the preferred color scheme will be reset to no preference. Therefore
+      // the preferred color scheme will be reset to 'light'. Therefore
       // when enabling force dark, we also set the preferred color scheme to
       // dark so that dark themed content will be preferred over force
       // darkening.
@@ -558,8 +557,7 @@ void AwSettings::PopulateWebPreferencesLocked(JNIEnv* env,
       }
     }
   } else {
-    web_prefs->preferred_color_scheme =
-        blink::PreferredColorScheme::kNoPreference;
+    web_prefs->preferred_color_scheme = blink::PreferredColorScheme::kLight;
     web_prefs->force_dark_mode_enabled = false;
   }
 }

android_webview/javatests/src/org/chromium/android_webview/test/DarkModeTest.java

@@ -49,7 +49,7 @@ public class DarkModeTest {
     @SmallTest
     public void testUAOnlyDarkening() throws Throwable {
         // If WebView uses UA only darkening strategy prefer-color-scheme should always been set to
-        // NoPreference to avoid double darkening regardless whether web-page supports dark theme.
+        // 'light' to avoid double darkening regardless whether web-page supports dark theme.
         mSettings.setForceDarkMode(ForceDarkMode.FORCE_DARK_ON);
         mSettings.setForceDarkBehavior(ForceDarkBehavior.FORCE_DARK_ONLY);
 
@@ -89,7 +89,7 @@ public class DarkModeTest {
         mSettings.setForceDarkMode(ForceDarkMode.FORCE_DARK_ON);
         mSettings.setForceDarkBehavior(ForceDarkBehavior.PREFER_MEDIA_QUERY_OVER_FORCE_DARK);
 
-        // If web page does not support dark theme prefer-color-scheme should be set to NoPreference
+        // If web page does not support dark theme prefer-color-scheme should be set to 'light'
         assertNotDarkScheme(mContents);
 
         final String supportsDarkScheme =

chrome/browser/chrome_content_browser_client.cc

@@ -3436,11 +3436,9 @@ void ChromeContentBrowserClient::OverrideWebkitPrefs(
       web_prefs->preferred_color_scheme = blink::PreferredColorScheme::kDark;
       break;
     case ui::NativeTheme::PreferredColorScheme::kLight:
+    case ui::NativeTheme::PreferredColorScheme::kNoPreference:
       web_prefs->preferred_color_scheme = blink::PreferredColorScheme::kLight;
       break;
-    case ui::NativeTheme::PreferredColorScheme::kNoPreference:
-      web_prefs->preferred_color_scheme =
-          blink::PreferredColorScheme::kNoPreference;
   }
 #endif  // !defined(OS_ANDROID)
 

content/public/common/common_param_traits_macros.h

@@ -77,7 +77,7 @@ IPC_ENUM_TRAITS_MIN_MAX_VALUE(
     content::AutoplayPolicy::kNoUserGestureRequired,
     content::AutoplayPolicy::kDocumentUserActivationRequired)
 IPC_ENUM_TRAITS_MIN_MAX_VALUE(blink::PreferredColorScheme,
-                              blink::PreferredColorScheme::kNoPreference,
+                              blink::PreferredColorScheme::kDark,
                               blink::PreferredColorScheme::kMaxValue)
 
 IPC_STRUCT_TRAITS_BEGIN(blink::WebRect)

content/public/common/web_preferences.cc

@@ -223,7 +223,6 @@ WebPreferences::WebPreferences()
       media_controls_enabled(true),
       do_not_update_selection_on_mutating_selection_range(false),
       autoplay_policy(AutoplayPolicy::kDocumentUserActivationRequired),
-      preferred_color_scheme(blink::PreferredColorScheme::kNoPreference),
       low_priority_iframes_threshold(net::EFFECTIVE_CONNECTION_TYPE_UNKNOWN),
       picture_in_picture_enabled(true),
       translate_service_available(false),

content/public/common/web_preferences.h

@@ -319,7 +319,7 @@ struct CONTENT_EXPORT WebPreferences {
   // evaluate the prefers-color-scheme media query and resolve UA color scheme
   // to be used based on the supported-color-schemes META tag and CSS property.
   blink::PreferredColorScheme preferred_color_scheme =
-      blink::PreferredColorScheme::kNoPreference;
+      blink::PreferredColorScheme::kLight;
 
   // Network quality threshold below which resources from iframes are assigned
   // either kVeryLow or kVeryLow Blink priority.

third_party/blink/public/common/css/preferred_color_scheme.h

@@ -9,7 +9,6 @@ namespace blink {
 
 // Use for passing preferred color scheme from the OS to the renderer.
 enum class PreferredColorScheme {
-  kNoPreference,
   kDark,
   kLight,
   kMaxValue = kLight,

third_party/blink/renderer/core/css/media_query_evaluator.cc

@@ -829,14 +829,12 @@ static bool PrefersColorSchemeMediaFeatureEval(
       media_values.GetPreferredColorScheme();
 
   if (!value.IsValid())
-    return preferred_scheme != PreferredColorScheme::kNoPreference;
+    return true;
 
   if (!value.is_id)
     return false;
 
-  return (preferred_scheme == PreferredColorScheme::kNoPreference &&
-          value.id == CSSValueID::kNoPreference) ||
-         (preferred_scheme == PreferredColorScheme::kDark &&
+  return (preferred_scheme == PreferredColorScheme::kDark &&
           value.id == CSSValueID::kDark) ||
          (preferred_scheme == PreferredColorScheme::kLight &&
           value.id == CSSValueID::kLight);

third_party/blink/renderer/core/css/media_query_exp.cc

@@ -76,10 +76,8 @@ static inline bool FeatureWithValidIdent(const String& media_feature,
            ident == CSSValueID::kRec2020;
   }
 
-  if (media_feature == media_feature_names::kPrefersColorSchemeMediaFeature) {
-    return ident == CSSValueID::kNoPreference || ident == CSSValueID::kDark ||
-           ident == CSSValueID::kLight;
-  }
+  if (media_feature == media_feature_names::kPrefersColorSchemeMediaFeature)
+    return ident == CSSValueID::kDark || ident == CSSValueID::kLight;
 
   if (media_feature == media_feature_names::kPrefersReducedMotionMediaFeature)
     return ident == CSSValueID::kNoPreference || ident == CSSValueID::kReduce;

third_party/blink/renderer/core/css/media_values.cc

@@ -28,15 +28,13 @@ namespace blink {
 
 PreferredColorScheme CSSValueIDToPreferredColorScheme(CSSValueID id) {
   switch (id) {
-    case CSSValueID::kNoPreference:
-      return PreferredColorScheme::kNoPreference;
     case CSSValueID::kLight:
       return PreferredColorScheme::kLight;
     case CSSValueID::kDark:
       return PreferredColorScheme::kDark;
     default:
       NOTREACHED();
-      return PreferredColorScheme::kNoPreference;
+      return PreferredColorScheme::kLight;
   }
 }
 

third_party/blink/renderer/core/css/media_values_cached.cc

@@ -34,7 +34,7 @@ MediaValuesCached::MediaValuesCachedData::MediaValuesCachedData()
       strict_mode(true),
       display_mode(blink::mojom::DisplayMode::kBrowser),
       color_gamut(ColorSpaceGamut::kUnknown),
-      preferred_color_scheme(PreferredColorScheme::kNoPreference),
+      preferred_color_scheme(PreferredColorScheme::kLight),
       prefers_reduced_motion(false),
       forced_colors(ForcedColors::kNone),
       navigation_controls(NavigationControls::kNone),

third_party/blink/renderer/core/css/style_engine.cc

@@ -2120,7 +2120,7 @@ void StyleEngine::UpdateColorScheme() {
   if (!SupportsDarkColorScheme() && settings->GetForceDarkModeEnabled()) {
     // Make sure we don't match (prefers-color-scheme: dark) when forced
     // darkening is enabled.
-    preferred_color_scheme_ = PreferredColorScheme::kNoPreference;
+    preferred_color_scheme_ = PreferredColorScheme::kLight;
   }
   if (GetDocument().Printing())
     preferred_color_scheme_ = PreferredColorScheme::kLight;

third_party/blink/renderer/core/css/style_engine.h

@@ -606,9 +606,8 @@ class CORE_EXPORT StyleEngine final : public GarbageCollected<StyleEngine>,
 
   // The preferred color scheme is set in settings, but may be overridden by the
   // ForceDarkMode setting where the preferred_color_scheme_ will be set to
-  // kNoPreference to avoid dark styling to be applied before auto darkening.
-  PreferredColorScheme preferred_color_scheme_ =
-      PreferredColorScheme::kNoPreference;
+  // kLight to avoid dark styling to be applied before auto darkening.
+  PreferredColorScheme preferred_color_scheme_ = PreferredColorScheme::kLight;
   bool use_dark_background_ = false;
 
   // Forced colors is set in WebThemeEngine.

third_party/blink/renderer/core/css/style_engine_test.cc

@@ -1519,7 +1519,7 @@ TEST_F(StyleEngineTest, MediaQueriesChangeColorSchemeForcedDarkMode) {
 
   GetDocument().body()->setInnerHTML(R"HTML(
     <style>
-      @media (prefers-color-scheme: no-preference) {
+      @media (prefers-color-scheme: light) {
         body { color: green }
       }
       @media (prefers-color-scheme: dark) {
@@ -1637,14 +1637,6 @@ TEST_F(StyleEngineTest, MediaQueriesChangeForcedColorsAndPreferredColorScheme) {
             GetDocument().body()->GetComputedStyle()->VisitedDependentColor(
                 GetCSSPropertyColor()));
 
-  // ForcedColors = kActive, PreferredColorScheme = kNoPreference
-  color_scheme_helper.SetPreferredColorScheme(
-      PreferredColorScheme::kNoPreference);
-  UpdateAllLifecyclePhases();
-  EXPECT_EQ(MakeRGB(255, 255, 0),
-            GetDocument().body()->GetComputedStyle()->VisitedDependentColor(
-                GetCSSPropertyColor()));
-
   // ForcedColors = kActive, PreferredColorScheme = kLight
   color_scheme_helper.SetPreferredColorScheme(PreferredColorScheme::kLight);
   UpdateAllLifecyclePhases();

third_party/blink/renderer/core/frame/settings.json5

@@ -1057,7 +1057,7 @@
     // evaluating the prefers-color-scheme media query.
     {
       name: "preferredColorScheme",
-      initial: "PreferredColorScheme::kNoPreference",
+      initial: "PreferredColorScheme::kLight",
       invalidate: "ColorScheme",
       type: "PreferredColorScheme",
     },

third_party/blink/renderer/core/testing/color_scheme_helper.h

@@ -33,7 +33,7 @@ class ColorSchemeHelper {
   WebThemeEngine* web_theme_engine_ = nullptr;
   Settings& settings_;
   PreferredColorScheme default_preferred_color_scheme_ =
-      PreferredColorScheme::kNoPreference;
+      PreferredColorScheme::kLight;
   ForcedColors default_forced_colors_ = ForcedColors::kNone;
 };
 

third_party/blink/web_tests/external/wpt/css/mediaqueries/prefers-color-scheme-expected.txt

-This is a testharness.js-based test.
-PASS Should be parseable in a CSS stylesheet: '(prefers-color-scheme)'
-PASS Should be parseable in a CSS stylesheet: '(prefers-color-scheme: light)'
-PASS Should be parseable in a CSS stylesheet: '(prefers-color-scheme: dark)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: 0)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: none)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: 10px)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: dark 0)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: dark light)'
-PASS Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: light/dark)'
-FAIL Should not be parseable in a CSS stylesheet: '(prefers-color-scheme: no-preference)' assert_false: expected false got true
-PASS Should be parseable in JS: '(prefers-color-scheme)'
-PASS Should be parseable in JS: '(prefers-color-scheme: light)'
-PASS Should be parseable in JS: '(prefers-color-scheme: dark)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: 0)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: none)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: 10px)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: dark 0)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: dark light)'
-PASS Should not be parseable in JS: '(prefers-color-scheme: light/dark)'
-FAIL Should not be parseable in JS: '(prefers-color-scheme: no-preference)' assert_false: expected false got true
-PASS Check that prefer-color-scheme evaluates to true in the boolean context
-Harness: the test ran to completion.
-

third_party/blink/web_tests/inspector-protocol/emulation/set-css-media-feature-override-expected.txt

 Tests that CSS media features can be overridden.
 matchMedia("(prefers-color-scheme: __invalid__)").matches: false
 matchMedia("(prefers-color-scheme: __invalid__)").matches applied: 3px x 2px
-matchMedia("(prefers-color-scheme: no-preference)").matches: true
-matchMedia("(prefers-color-scheme: no-preference)").matches applied: 2px x 2px
+matchMedia("(prefers-color-scheme: no-preference)").matches: false
+matchMedia("(prefers-color-scheme: no-preference)").matches applied: 3px x 2px
 matchMedia("(prefers-color-scheme: light)").matches: true
 matchMedia("(prefers-color-scheme: light)").matches applied: 3px x 2px
 matchMedia("(prefers-color-scheme: dark)").matches: true