Use TDA for background color instead of new color layer

Bug: 205274345
Bug: 202856837
Bug: 203567491
Test: Run task animations and make sure background color shows
Change-Id: I57fa88c6f45adca9e3301b39e868bd127644b76f

services/core/java/com/android/server/wm/TaskDisplayArea.java

@@ -47,6 +47,7 @@ import android.annotation.Nullable;
 import android.app.ActivityOptions;
 import android.app.WindowConfiguration;
 import android.content.res.Configuration;
+import android.graphics.Color;
 import android.os.UserHandle;
 import android.util.IntArray;
 import android.util.Slog;
@@ -80,9 +81,9 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
     DisplayContent mDisplayContent;
 
     /**
-     * A color layer that serves as a solid color background to certain animations.
+     * Keeps track of the last set color layer so that it can be reset during surface migrations.
      */
-    private SurfaceControl mColorBackgroundLayer;
+    private @ColorInt int mBackgroundColor = 0;
 
     /**
      * This counter is used to make sure we don't prematurely clear the background color in the
@@ -355,6 +356,14 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
         }
     }
 
+    @Override
+    void setInitialSurfaceControlProperties(SurfaceControl.Builder b) {
+        // We want an effect layer instead of the default container layer so that we can set a
+        // background color on it for task animations.
+        b.setEffectLayer();
+        super.setInitialSurfaceControlProperties(b);
+    }
+
     @Override
     void addChild(WindowContainer child, int position) {
         if (child.asTaskDisplayArea() != null) {
@@ -874,11 +883,6 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
     void onParentChanged(ConfigurationContainer newParent, ConfigurationContainer oldParent) {
         if (getParent() != null) {
             super.onParentChanged(newParent, oldParent, () -> {
-                mColorBackgroundLayer = makeChildSurface(null)
-                        .setColorLayer()
-                        .setName("colorBackgroundLayer")
-                        .setCallsite("TaskDisplayArea.onParentChanged")
-                        .build();
                 mSplitScreenDividerAnchor = makeChildSurface(null)
                         .setName("splitScreenDividerAnchor")
                         .setCallsite("TaskDisplayArea.onParentChanged")
@@ -890,28 +894,18 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
         } else {
             super.onParentChanged(newParent, oldParent);
             mWmService.mTransactionFactory.get()
-                    .remove(mColorBackgroundLayer)
                     .remove(mSplitScreenDividerAnchor)
                     .apply();
-            mColorBackgroundLayer = null;
             mSplitScreenDividerAnchor = null;
         }
     }
 
-    void setBackgroundColor(@ColorInt int color) {
-        if (mColorBackgroundLayer == null) {
-            return;
-        }
-
-        float r = ((color >> 16) & 0xff) / 255.0f;
-        float g = ((color >>  8) & 0xff) / 255.0f;
-        float b = ((color >>  0) & 0xff) / 255.0f;
-
+    void setBackgroundColor(@ColorInt int colorInt) {
+        mBackgroundColor = colorInt;
+        Color color = Color.valueOf(colorInt);
         mColorLayerCounter++;
-
         getPendingTransaction()
-                .setColor(mColorBackgroundLayer, new float[]{r, g, b})
-                .show(mColorBackgroundLayer);
+                .setColor(mSurfaceControl, new float[]{color.red(), color.green(), color.blue()});
 
         scheduleAnimation();
     }
@@ -922,7 +916,7 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
         // Only clear the color layer if we have received the same amounts of clear as set
         // requests.
         if (mColorLayerCounter == 0) {
-            getPendingTransaction().hide(mColorBackgroundLayer);
+            getPendingTransaction().unsetColor(mSurfaceControl);
             scheduleAnimation();
         }
     }
@@ -930,12 +924,16 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
     @Override
     void migrateToNewSurfaceControl(SurfaceControl.Transaction t) {
         super.migrateToNewSurfaceControl(t);
-        if (mColorBackgroundLayer == null) {
+
+        if (mColorLayerCounter > 0) {
+            setBackgroundColor(mBackgroundColor);
+        }
+
+        if (mSplitScreenDividerAnchor == null) {
             return;
         }
 
         // As TaskDisplayArea is getting a new surface, reparent and reorder the child surfaces.
-        t.reparent(mColorBackgroundLayer, mSurfaceControl);
         t.reparent(mSplitScreenDividerAnchor, mSurfaceControl);
         reassignLayer(t);
         scheduleAnimation();