Add TODO comments

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/java/com/owncloud/android/ui/activity/FileDisplayActivity.java

@@ -1018,6 +1018,7 @@ public class FileDisplayActivity extends FileActivity
      */
     @SuppressFBWarnings("ITC_INHERITANCE_TYPE_CHECKING")
     @Override
+    // TODO Apply fast fail principle
     public void onBackPressed() {
         if (isSearchOpen()) {
             resetSearchAction();

app/src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java

@@ -923,6 +923,8 @@ public class OCFileListFragment extends ExtendedListFragment implements
      * <p>
      * return       Count of folder levels browsed up.
      */
+
+    // TODO Apply fast fail principle
     public int onBrowseUp() {
         OCFile parentDir;
         int moveCount = 0;