Add contextual card dismissal implementation

When users clcik on the remove button in dismissal view, the card should
be marked as dismissed in the database, and the UI should be refreshed.

Bug: 113783548, 119594116
Test: robotests
Change-Id: I980600c4c0753ad5abc52ae63bac7196a4b818f1

src/com/android/settings/homepage/contextualcards/ContextualCardLoader.java

@@ -24,8 +24,11 @@ import android.content.ContentProviderClient;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.pm.PackageManager;
+import android.database.ContentObserver;
 import android.database.Cursor;
 import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
 import android.util.Log;
 
 import androidx.annotation.NonNull;
@@ -60,6 +63,19 @@ public class ContextualCardLoader extends AsyncLoaderCompat<List<ContextualCard>
         mContext = context.getApplicationContext();
     }
 
+    @Override
+    protected void onStartLoading() {
+        super.onStartLoading();
+        mContext.getContentResolver().registerContentObserver(CardContentProvider.URI,
+                false /*notifyForDescendants*/, mObserver);
+    }
+
+    @Override
+    protected void onStopLoading() {
+        super.onStopLoading();
+        mContext.getContentResolver().unregisterContentObserver(mObserver);
+    }
+
     @Override
     protected void onDiscardResult(List<ContextualCard> result) {
 
@@ -184,4 +200,14 @@ public class ContextualCardLoader extends AsyncLoaderCompat<List<ContextualCard>
         }
         return -1L;
     }
+
+    private final ContentObserver mObserver = new ContentObserver(
+            new Handler(Looper.getMainLooper())) {
+        @Override
+        public void onChange(boolean selfChange) {
+            if (isStarted()) {
+                forceLoad();
+            }
+        }
+    };
 }