Add dynamic group panel

-Rename PanelCustomizedButtonCallback to PanelContentCallback
-Add onGroupChanged in PanelContentCallback
-Add test cases

Bug: 146813761
Test: make -j42 RunSettingsRoboTests
Change-Id: I60888efbbd0fc2878467418e55c70887a9d3f405

src/com/android/settings/panel/PanelFragment.java

@@ -411,7 +411,7 @@ public class PanelFragment extends Fragment {
         };
     }
 
-    class LocalPanelCallback implements PanelCustomizedButtonCallback {
+    class LocalPanelCallback implements PanelContentCallback {
 
         @Override
         public void onCustomizedButtonStateChanged() {
@@ -420,5 +420,12 @@ public class PanelFragment extends Fragment {
                         mPanel.isCustomizedButtonUsed() ? View.VISIBLE : View.GONE);
             });
         }
+
+        @Override
+        public void onGroupChanged() {
+            ThreadUtils.postOnMainThread(() -> {
+                mHeaderSubtitle.setText(mPanel.getSubTitle());
+            });
+        }
     }
 }