Cleans up fragments when removed

 Bug: 3198097
 This change fixes it so that when the Combined view is removed,
 it also removes any added fragments. This fixes the issue where
 "Clear History" menu option would still be displayed after leaving
 the history view.

Change-Id: I7ff995d856ef21be1900f90ece2efaf3d4e19f8b
diff --git a/src/com/android/browser/CombinedBookmarkHistoryView.java b/src/com/android/browser/CombinedBookmarkHistoryView.java
index 4f6f10c..9ac357f 100644
--- a/src/com/android/browser/CombinedBookmarkHistoryView.java
+++ b/src/com/android/browser/CombinedBookmarkHistoryView.java
@@ -200,6 +200,19 @@
     }
 
     @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+        FragmentManager fm = mActivity.getFragmentManager();
+        FragmentTransaction transaction = fm.openTransaction();
+        if (mCurrentFragment == FRAGMENT_ID_BOOKMARKS) {
+            transaction.remove(mBookmarks);
+        } else if (mCurrentFragment == FRAGMENT_ID_HISTORY) {
+            transaction.remove(mHistory);
+        }
+        transaction.commit();
+    }
+
+    @Override
     public void onClick(View view) {
         if ((mTabHistory == view) && (mCurrentFragment != FRAGMENT_ID_HISTORY)) {
             loadFragment(FRAGMENT_ID_HISTORY, mExtras, false);