Closes #8752 - Use coverUntilFirstPaint() with PreferredColorScheme

components/browser/engine-gecko-nightly/src/main/java/mozilla/components/browser/engine/gecko/GeckoEngine.kt

@@ -144,7 +144,9 @@ class GeckoEngine(
      * Creates a new Gecko-based EngineView.
      */
     override fun createView(context: Context, attrs: AttributeSet?): EngineView {
-        return GeckoEngineView(context, attrs)
+        return GeckoEngineView(context, attrs).apply {
+            setColorScheme(settings.preferredColorScheme)
+        }
     }
 
     /**

components/browser/engine-gecko-nightly/src/main/java/mozilla/components/browser/engine/gecko/GeckoEngineView.kt

@@ -5,14 +5,17 @@
 package mozilla.components.browser.engine.gecko
 
 import android.content.Context
+import android.content.res.Configuration
 import android.graphics.Bitmap
+import android.graphics.Color
 import android.util.AttributeSet
 import android.widget.FrameLayout
 import androidx.annotation.VisibleForTesting
 import androidx.core.view.ViewCompat
 import mozilla.components.browser.engine.gecko.selection.GeckoSelectionActionDelegate
 import mozilla.components.concept.engine.EngineSession
 import mozilla.components.concept.engine.EngineView
+import mozilla.components.concept.engine.mediaquery.PreferredColorScheme
 import mozilla.components.concept.engine.selection.SelectionActionDelegate
 import org.mozilla.geckoview.BasicSelectionActionDelegate
 import org.mozilla.geckoview.GeckoResult
@@ -38,7 +41,7 @@ class GeckoEngineView @JvmOverloads constructor(
                 val otherActivityClassName =
                     this.session?.accessibility?.view?.context?.javaClass?.simpleName
                 val otherActivityClassHashcode =
-                        this.session?.accessibility?.view?.context?.hashCode()
+                    this.session?.accessibility?.view?.context?.hashCode()
                 val activityClassName = context.javaClass.simpleName
                 val activityClassHashCode = context.hashCode()
                 val msg = "ATTACH VIEW: Current activity: $activityClassName hashcode " +
@@ -47,6 +50,7 @@ class GeckoEngineView @JvmOverloads constructor(
                 throw IllegalStateException(msg, e)
             }
         }
+
         override fun onDetachedFromWindow() {
             // We are releasing the session before GeckoView gets detached from the window. Otherwise
             // GeckoView will close the session automatically and we do not want that.
@@ -61,6 +65,26 @@ class GeckoEngineView @JvmOverloads constructor(
         ViewCompat.setImportantForAutofill(this, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES)
     }
 
+    internal fun setColorScheme(preferredColorScheme: PreferredColorScheme) {
+        var colorScheme = preferredColorScheme
+        if (preferredColorScheme == PreferredColorScheme.System) {
+            colorScheme =
+                if (context.resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
+                    == Configuration.UI_MODE_NIGHT_YES
+                ) {
+                    PreferredColorScheme.Dark
+                } else {
+                    PreferredColorScheme.Light
+                }
+        }
+
+        if (colorScheme == PreferredColorScheme.Dark) {
+            geckoView.coverUntilFirstPaint(DARK_COVER)
+        } else {
+            geckoView.coverUntilFirstPaint(Color.WHITE)
+        }
+    }
+
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
     internal var currentSession: GeckoEngineSession? = null
 
@@ -142,7 +166,8 @@ class GeckoEngineView @JvmOverloads constructor(
 
     override fun canScrollVerticallyUp() = currentSession?.let { it.scrollY > 0 } != false
 
-    override fun canScrollVerticallyDown() = true // waiting for this issue https://bugzilla.mozilla.org/show_bug.cgi?id=1507569
+    override fun canScrollVerticallyDown() =
+        true // waiting for this issue https://bugzilla.mozilla.org/show_bug.cgi?id=1507569
 
     override fun getInputResult(): EngineView.InputResult {
         // Direct mapping of GeckoView's returned values.
@@ -192,4 +217,8 @@ class GeckoEngineView @JvmOverloads constructor(
         geckoView.visibility = visibility
         super.setVisibility(visibility)
     }
+
+    companion object {
+        internal const val DARK_COVER = 0xFF2A2A2E.toInt()
+    }
 }

components/browser/engine-gecko-nightly/src/test/java/mozilla/components/browser/engine/gecko/GeckoEngineViewTest.kt

@@ -7,9 +7,12 @@ package mozilla.components.browser.engine.gecko
 import android.app.Activity
 import android.content.Context
 import android.graphics.Bitmap
+import android.graphics.Color
 import android.view.View
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import mozilla.components.browser.engine.gecko.GeckoEngineView.Companion.DARK_COVER
 import mozilla.components.browser.engine.gecko.selection.GeckoSelectionActionDelegate
+import mozilla.components.concept.engine.mediaquery.PreferredColorScheme
 import mozilla.components.concept.engine.selection.SelectionActionDelegate
 import mozilla.components.support.test.argumentCaptor
 import mozilla.components.support.test.mock
@@ -104,6 +107,23 @@ class GeckoEngineViewTest {
         verify(engineView.currentSelection)?.clearSelection()
     }
 
+    @Test
+    fun `setColorScheme uses preferred color scheme to set correct cover color`() {
+        val engineView = GeckoEngineView(context)
+
+        engineView.geckoView = mock()
+
+        var preferredColorScheme: PreferredColorScheme = PreferredColorScheme.Light
+
+        engineView.setColorScheme(preferredColorScheme)
+
+        verify(engineView.geckoView)?.coverUntilFirstPaint(Color.WHITE)
+
+        preferredColorScheme = PreferredColorScheme.Dark
+        engineView.setColorScheme(preferredColorScheme)
+        verify(engineView.geckoView)?.coverUntilFirstPaint(DARK_COVER)
+    }
+
     @Test
     fun `setVerticalClipping is forwarded to GeckoView instance`() {
         val engineView = GeckoEngineView(context)

docs/changelog.md

@@ -15,6 +15,10 @@ permalink: /changelog/
 * **feature-downloads**
   * 🚒 Bug fixed [issue #8823](https://github.com/mozilla-mobile/android-components/issues/8823) Downloads for data URLs were failing on nightly and beta more details in the [Fenix issue](https://github.com/mozilla-mobile/fenix/issues/16228#issuecomment-717976737).
 
+* **browser-engine-gecko-nightly**
+  * Adds optional `PreferredColorScheme` param to `GeckoEngineView`
+  * On `GeckoView` init call `coverUntilFirstPaint()` with `PreferredColorScheme`
+
 # 64.0.0
 
 * [Commits](https://github.com/mozilla-mobile/android-components/compare/v63.0.0...v64.0.0)