Temporarily allow StackView to use a canvas.clipRectUnion

StackView currently expands the clip of the view which is a prohibited
operation in API Level 28.  This CL currently allows this specialized
use case to work in this situation until we can update StackView
to not clip to its bounds and then just intersect with this clip
provided by its parent.

Test: CtsWidgetTestCases
Bug: 77642155
Change-Id: Icc003ad3946bb226368ec2030d4707753f4f55e9

core/java/android/widget/StackView.java

@@ -28,7 +28,6 @@ import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.Rect;
 import android.graphics.RectF;
-import android.graphics.Region;
 import android.graphics.TableMaskFilter;
 import android.os.Bundle;
 import android.util.AttributeSet;
@@ -550,8 +549,8 @@ public class StackView extends AdapterViewAnimator {
 
         // We only expand the clip bounds if necessary.
         if (expandClipRegion) {
-            canvas.save(Canvas.CLIP_SAVE_FLAG);
-            canvas.clipRect(stackInvalidateRect, Region.Op.UNION);
+            canvas.save();
+            canvas.clipRectUnion(stackInvalidateRect);
             super.dispatchDraw(canvas);
             canvas.restore();
         } else {

graphics/java/android/graphics/Canvas.java

@@ -828,6 +828,17 @@ public class Canvas extends BaseCanvas {
                 op.nativeInt);
     }
 
+    /**
+     * DON'T USE THIS METHOD.  It exists only to support a particular legacy behavior in
+     * the view system and will be removed as soon as that code is refactored to no longer
+     * depend on this behavior.
+     * @hide
+     */
+    public boolean clipRectUnion(@NonNull Rect rect) {
+        return nClipRect(mNativeCanvasWrapper, rect.left, rect.top, rect.right, rect.bottom,
+                Region.Op.UNION.nativeInt);
+    }
+
     /**
      * Intersect the current clip with the specified rectangle, which is
      * expressed in local coordinates.