Add indexeddb-use-leveldb to about:flags.

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index a598dfe6cee82fe74f922a746b4b8174ddcfcde9..61f5332f97b1a3bcc7088aad3d8a2a382907435f 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -4264,6 +4264,12 @@ Keep your key file in a safe place. You will need it to create new versions of y
       <message name="IDS_FLAGS_RESTRICT_INSTANT_TO_SEARCH_DESCRIPTION" desc="Description for the flag to restrict Instant to search">
         Restrict Instant to loading only search pages.
       </message>
+      <message name="IDS_FLAGS_INDEXEDDB_USE_LEVELDB_NAME" desc="Title for the flag to use the LevelDB back-end for IndexedDB">
+        IndexedDB use LevelDB.
+      </message>
+      <message name="IDS_FLAGS_INDEXEDDB_USE_LEVELDB_DESCRIPTION" desc="Description for the flag to use the LevelDB back-end for IndexedDB">
+        Enable the experimental LevelDB back-end for IndexedDB.
+      </message>
 
       <!-- Crashes -->
       <message name="IDS_CRASHES_TITLE" desc="Title for the chrome://crashes page.">