Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/1d677cdfd7cf
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #19627 from cctuan/987487-2

Bug 987487 - [Gaia] [Build] Refactoring webapp-optimize.js and unit tests

========

https://hg.mozilla.org/integration/gaia-central/rev/9fe7db7c3b89
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 987487 - [Gaia] [Build] Refactoring webapp-optimize.js and unit tests

========

https://hg.mozilla.org/integration/gaia-central/rev/cb02ccefc7cf
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #19729 from etiennesegonzac/bug-1011312-sheet-transition-cleanup

Bug 1011312 - Cleaning up the styles of the previous sheets before r=alive

========

https://hg.mozilla.org/integration/gaia-central/rev/f58562f8851e
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1011312 - Cleaning up the styles of the previous sheets before starting a SheetTransition.

b2g/config/gaia.json

@@ -4,6 +4,6 @@
         "remote": "", 
         "branch": ""
     }, 
-    "revision": "e2bcecc1a7783d93cda15d9b91c57085ef2a37bc", 
+    "revision": "1d677cdfd7cf03bbaea07a176ad4d11e63976fcb", 
     "repo_path": "/integration/gaia-central"
 }