Doc fix: update Displaying Bitmaps training class code snippet
Bug: 11372790

Change-Id: Ifb484b03ac4085eeccadb1602dace37690dc2d6b
diff --git a/docs/html/training/displaying-bitmaps/cache-bitmap.jd b/docs/html/training/displaying-bitmaps/cache-bitmap.jd
index 25efe1e..ad084c2 100644
--- a/docs/html/training/displaying-bitmaps/cache-bitmap.jd
+++ b/docs/html/training/displaying-bitmaps/cache-bitmap.jd
@@ -346,6 +346,7 @@
         RetainFragment fragment = (RetainFragment) fm.findFragmentByTag(TAG);
         if (fragment == null) {
             fragment = new RetainFragment();
+            fm.beginTransaction().add(fragment, TAG).commit();
         }
         return fragment;
     }