Make the Android dark theme flag enabled by default

Bug: 1018268
Change-Id: Ib5a8e881fc958715984d40188e3f3bb054b40427
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894412
Commit-Queue: Sinan Sahin <sinansahin@google.com>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713150}

chrome/android/java/src/org/chromium/chrome/browser/flags/FeatureUtilities.java

@@ -410,7 +410,7 @@ public class FeatureUtilities {
      *         enabled).
      */
     public static boolean isNightModeAvailable() {
-        return isFlagEnabled(NIGHT_MODE_AVAILABLE_KEY, false);
+        return isFlagEnabled(NIGHT_MODE_AVAILABLE_KEY, true);
     }
 
     /**
@@ -435,7 +435,7 @@ public class FeatureUtilities {
 
         String lightModeDefaultParam = "default_light_theme";
         boolean lightModeAsDefault = ChromeFeatureList.getFieldTrialParamByFeatureAsBoolean(
-                ChromeFeatureList.ANDROID_NIGHT_MODE, lightModeDefaultParam, false);
+                ChromeFeatureList.ANDROID_NIGHT_MODE, lightModeDefaultParam, true);
 
         SharedPreferencesManager.getInstance().writeBoolean(
                 NIGHT_MODE_DEFAULT_TO_LIGHT, lightModeAsDefault);
@@ -448,7 +448,7 @@ public class FeatureUtilities {
         if (BuildInfo.isAtLeastQ()) {
             return false;
         }
-        return isFlagEnabled(NIGHT_MODE_DEFAULT_TO_LIGHT, false);
+        return isFlagEnabled(NIGHT_MODE_DEFAULT_TO_LIGHT, true);
     }
 
     /**

chrome/android/javatests/src/org/chromium/chrome/browser/preferences/themes/ThemePreferencesTest.java

@@ -71,7 +71,9 @@ public class ThemePreferencesTest extends DummyUiActivityTestCase {
 
     @Override
     public void tearDownTest() throws Exception {
-        SharedPreferencesManager.getInstance().removeKey(UI_THEME_SETTING_KEY);
+        TestThreadUtils.runOnUiThreadBlocking(
+                () -> SharedPreferencesManager.getInstance().removeKey(UI_THEME_SETTING_KEY));
+
         FeatureUtilities.setNightModeDefaultToLightForTesting(null);
         super.tearDownTest();
     }

chrome/android/junit/src/org/chromium/chrome/browser/night_mode/GlobalNightModeStateControllerTest.java

@@ -94,7 +94,12 @@ public class GlobalNightModeStateControllerTest {
     }
 
     @Test
-    public void testUpdateNightMode_PowerSaveMode() {
+    public void testUpdateNightMode_PowerSaveMode_DefaultsToSystem() {
+        // Set preference to system default and verify that the night mode isn't enabled.
+        SharedPreferencesManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.SYSTEM_DEFAULT);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
         // Enable power save mode and verify night mode is enabled.
         setIsPowerSaveMode(true);
         assertTrue(mGlobalNightModeStateController.isInNightMode());
@@ -117,7 +122,12 @@ public class GlobalNightModeStateControllerTest {
     }
 
     @Test
-    public void testUpdateNightMode_SystemNightMode() {
+    public void testUpdateNightMode_SystemNightMode_DefaultsToSystem() {
+        // Set preference to system default and verify that the night mode isn't enabled.
+        SharedPreferencesManager.getInstance().writeInt(
+                UI_THEME_SETTING_KEY, ThemePreferences.ThemeSetting.SYSTEM_DEFAULT);
+        assertFalse(mGlobalNightModeStateController.isInNightMode());
+
         // Enable system night mode and verify night mode is enabled.
         setSystemNightMode(true);
         assertTrue(mGlobalNightModeStateController.isInNightMode());

chrome/browser/android/chrome_feature_list.cc

@@ -249,7 +249,7 @@ const base::Feature kAdjustWebApkInstallationSpace = {
     "AdjustWebApkInstallationSpace", base::FEATURE_DISABLED_BY_DEFAULT};
 
 const base::Feature kAndroidNightMode{"AndroidNightMode",
-                                      base::FEATURE_DISABLED_BY_DEFAULT};
+                                      base::FEATURE_ENABLED_BY_DEFAULT};
 
 const base::Feature kAndroidNightModeCCT{"AndroidNightModeCCT",
                                          base::FEATURE_ENABLED_BY_DEFAULT};