Fix CCT night mode initial state

This fixes an error due to which AppCompatDelegate.setLocalNightMode
wasn't always triggered on CCT startup

Bug: 1012755
Change-Id: I5dce526db679ba36b667f6330bd94c577aef02a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1857318
Commit-Queue: Pavel Shmakov <pshmakov@chromium.org>
Commit-Queue: Theresa  <twellington@chromium.org>
Auto-Submit: Pavel Shmakov <pshmakov@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705289}

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabNightModeStateController.java

@@ -8,6 +8,7 @@ import android.content.Intent;
 import android.support.v7.app.AppCompatDelegate;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.browser.customtabs.CustomTabsIntent;
 
 import org.chromium.base.ObserverList;
@@ -38,7 +39,8 @@ public class CustomTabNightModeStateController implements Destroyable, NightMode
     private int mRequestedColorScheme;
     private AppCompatDelegate mAppCompatDelegate;
 
-    private boolean mIsInNightMode;
+    @Nullable // Null initially, so that the first update is always applied (see updateNightMode()).
+    private Boolean mIsInNightMode;
 
     CustomTabNightModeStateController(ActivityLifecycleDispatcher lifecycleDispatcher,
             SystemNightModeMonitor systemNightModeMonitor,
@@ -85,8 +87,7 @@ public class CustomTabNightModeStateController implements Destroyable, NightMode
     // NightModeStateProvider implementation.
     @Override
     public boolean isInNightMode() {
-        return mIsInNightMode;
-
+        return mIsInNightMode != null && mIsInNightMode;
     }
 
     @Override
@@ -108,7 +109,7 @@ public class CustomTabNightModeStateController implements Destroyable, NightMode
 
     private void updateNightMode() {
         boolean shouldBeInNightMode = shouldBeInNightMode();
-        if (mIsInNightMode == shouldBeInNightMode) return;
+        if (mIsInNightMode != null && mIsInNightMode == shouldBeInNightMode) return;
 
         mIsInNightMode = shouldBeInNightMode;
         mAppCompatDelegate.setLocalNightMode(mIsInNightMode ? AppCompatDelegate.MODE_NIGHT_YES

chrome/android/junit/src/org/chromium/chrome/browser/customtabs/CustomTabNightModeStateControllerTest.java

@@ -76,6 +76,20 @@ public class CustomTabNightModeStateControllerTest {
         FeatureUtilities.setNightModeForCustomTabsAvailableForTesting(false);
     }
 
+    @Test
+    public void triggersAppCompatDelegate_WhenInitialSchemeIsLight() {
+        setSystemNightMode(false);
+        initializeWithColorScheme(COLOR_SCHEME_SYSTEM);
+        verify(mAppCompatDelegate).setLocalNightMode(AppCompatDelegate.MODE_NIGHT_NO);
+    }
+
+    @Test
+    public void triggersAppCompatDelegate_WhenInitialSchemeIsDark() {
+        setSystemNightMode(true);
+        initializeWithColorScheme(COLOR_SCHEME_SYSTEM);
+        verify(mAppCompatDelegate).setLocalNightMode(AppCompatDelegate.MODE_NIGHT_YES);
+    }
+
     @Test
     public void nightModeIfOff_WhenSchemeForced() {
         initializeWithColorScheme(COLOR_SCHEME_LIGHT);