Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/b68d0a3caae2
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #20778 from KevinGrandon/bug_1027990_search_window_activities

Bug 1027990 - [System] ActivityWindow does not receive proper rearWindow

========

https://hg.mozilla.org/integration/gaia-central/rev/3bf378f39cf9
Author: vingtetun <21@vingtetun.org>
Desc: Bug 1027990 - Part 2, SearchWindow activity style fixes r=kgrandon

========

https://hg.mozilla.org/integration/gaia-central/rev/8696249dcc7c
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1027990 - [System] ActivityWindow does not receive proper rearWindow r=alive

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "4198778c9093f47cd2e7938273dec8f3bec8b4a5", 
+    "revision": "b68d0a3caae2abff5bbc2a96b568fbc3413e1d20", 
     "repo_path": "/integration/gaia-central"
 }