Fix the momery leak in DrawOverlayDetails

https://code.google.com/p/android/issues/detail?id=210852

we need to release the mOverlayBridge in onDestroy, or it will cause Memory Leak issue
Signed-off-by: 宋凯伦 <songkailun@xiaomi.com>

Change-Id: If0113ed72773c366596a2c915ec504c1c68fe3b7

src/com/android/settings/applications/DrawOverlayDetails.java

@@ -93,6 +93,12 @@ public class DrawOverlayDetails extends AppInfoWithHeader implements OnPreferenc
                 .setAction(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
     }
 
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        mOverlayBridge.release();
+    }
+
     @Override
     public boolean onPreferenceClick(Preference preference) {
         if (preference == mOverlayPrefs) {