Fix multiple chatcolors issues from beta feedback.

- Fix issue where custom color would come out as black
- Completely remove mask view in favour of using the item decoration.
- Fix issue where video gifs wouldn't "cut through" bubble.
- Fix issue where multiselect shade would only appear if bottom or top item was not visible

app/src/main/java/org/thoughtcrime/securesms/util/Projection.java

@@ -14,6 +14,9 @@ import androidx.recyclerview.widget.RecyclerView;
 import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.components.CornerMask;
 
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -159,6 +162,42 @@ public final class Projection {
     return new Projection(viewBounds.left, viewBounds.top, descendantProjection.width, descendantProjection.height, descendantProjection.corners);
   }
 
+  public static @NonNull List<Projection> getCapAndTail(@NonNull Projection parentProjection, @NonNull Projection childProjection) {
+    if (parentProjection.equals(childProjection)) {
+      return Collections.emptyList();
+    }
+
+    float topX      = parentProjection.x;
+    float topY      = parentProjection.y;
+    int   topWidth  = parentProjection.getWidth();
+    int   topHeight = (int) (childProjection.y - parentProjection.y);
+
+    final Corners topCorners;
+    Corners       parentCorners = parentProjection.getCorners();
+    if (parentCorners != null) {
+      topCorners = new Corners(parentCorners.topLeft, parentCorners.topRight, 0f, 0f);
+    } else {
+      topCorners = null;
+    }
+
+    float bottomX      = parentProjection.x;
+    float bottomY      = parentProjection.y + topHeight + childProjection.getHeight();
+    int   bottomWidth  = parentProjection.getWidth();
+    int   bottomHeight = (int) ((parentProjection.y + parentProjection.getHeight()) - bottomY);
+
+    final Corners bottomCorners;
+    if (parentCorners != null) {
+      bottomCorners = new Corners(0f, 0f, parentCorners.bottomRight, parentCorners.bottomLeft);
+    } else {
+      bottomCorners = null;
+    }
+
+    return Arrays.asList(
+        new Projection(topX, topY, topWidth, topHeight, topCorners),
+        new Projection(bottomX, bottomY, bottomWidth, bottomHeight, bottomCorners)
+    );
+  }
+
   public static final class Corners {
     private final float topLeft;
     private final float topRight;