Add support for creating Megaphones. Includes reactions megaphone.

app/src/main/java/org/thoughtcrime/securesms/reactions/ReactionsMegaphoneView.java

@@ -0,0 +1,37 @@
+package org.thoughtcrime.securesms.reactions;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.FrameLayout;
+
+import androidx.annotation.NonNull;
+
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.megaphone.Megaphone;
+import org.thoughtcrime.securesms.megaphone.MegaphoneListener;
+
+public class ReactionsMegaphoneView extends FrameLayout {
+
+  private View closeButton;
+
+  public ReactionsMegaphoneView(Context context) {
+    super(context);
+    initialize(context);
+  }
+
+  public ReactionsMegaphoneView(Context context, AttributeSet attrs) {
+    super(context, attrs);
+    initialize(context);
+  }
+
+  private void initialize(@NonNull Context context) {
+    inflate(context, R.layout.reactions_megaphone, this);
+
+    this.closeButton = findViewById(R.id.reactions_megaphone_x);
+  }
+
+  public void present(@NonNull Megaphone megaphone, @NonNull MegaphoneListener listener) {
+    this.closeButton.setOnClickListener(v -> listener.onMegaphoneCompleted(megaphone));
+  }
+}