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/MediaOutputPanel.java

@@ -66,7 +66,7 @@ public class MediaOutputPanel implements PanelContent, LocalMediaManager.DeviceC
     private final Context mContext;
     private final String mPackageName;
 
-    private PanelCustomizedButtonCallback mCallback;
+    private PanelContentCallback mCallback;
     private boolean mIsCustomizedButtonUsed = true;
 
     @VisibleForTesting
@@ -189,7 +189,7 @@ public class MediaOutputPanel implements PanelContent, LocalMediaManager.DeviceC
     }
 
     @Override
-    public void registerCallback(PanelCustomizedButtonCallback callback) {
+    public void registerCallback(PanelContentCallback callback) {
         mCallback = callback;
     }