Add vertical scrolling to Sticker Keyboard.

app/src/main/java/org/thoughtcrime/securesms/database/Database.java

@@ -76,6 +76,7 @@ public abstract class Database {
   }
 
   protected void notifyStickerPackListeners() {
+    ApplicationDependencies.getDatabaseObserver().notifyStickerPackObservers();
     context.getContentResolver().notifyChange(DatabaseContentProviders.StickerPack.CONTENT_URI, null);
   }
 

app/src/main/java/org/thoughtcrime/securesms/database/DatabaseObserver.java

@@ -30,6 +30,7 @@ public final class DatabaseObserver {
   private final Map<UUID, Set<Observer>> paymentObservers;
   private final Set<Observer>            allPaymentsObservers;
   private final Set<Observer>            chatColorsObservers;
+  private final Set<Observer>            stickerPackObservers;
 
   public DatabaseObserver(Application application) {
     this.application                  = application;
@@ -40,6 +41,7 @@ public final class DatabaseObserver {
     this.paymentObservers             = new HashMap<>();
     this.allPaymentsObservers         = new HashSet<>();
     this.chatColorsObservers          = new HashSet<>();
+    this.stickerPackObservers         = new HashSet<>();
   }
 
   public void registerConversationListObserver(@NonNull Observer listener) {
@@ -78,6 +80,12 @@ public final class DatabaseObserver {
     });
   }
 
+  public void registerStickerPackObserver(@NonNull Observer listener) {
+    executor.execute(() -> {
+      stickerPackObservers.add(listener);
+    });
+  }
+
   public void unregisterObserver(@NonNull Observer listener) {
     executor.execute(() -> {
       conversationListObservers.remove(listener);
@@ -85,6 +93,7 @@ public final class DatabaseObserver {
       unregisterMapped(verboseConversationObservers, listener);
       unregisterMapped(paymentObservers, listener);
       chatColorsObservers.remove(listener);
+      stickerPackObservers.remove(listener);
     });
   }
 
@@ -160,6 +169,12 @@ public final class DatabaseObserver {
     });
   }
 
+  public void notifyStickerPackObservers() {
+    executor.execute(() -> {
+      notifySet(stickerPackObservers);
+    });
+  }
+
   private <K> void registerMapped(@NonNull Map<K, Set<Observer>> map, @NonNull K key, @NonNull Observer listener) {
     Set<Observer> listeners = map.get(key);