Bumping gaia.json for 4 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/bf3a8d594a55
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Merge pull request #12102 from gabrielesvelto/bug-911955-ignore-non-si-sl-messages

Bug 911955 - Discard all non-SI/SL WAP Push messages r=vingtetun

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https://hg.mozilla.org/integration/gaia-central/rev/efff58ac137c
Author: Gabriele Svelto <gabriele.svelto@gmail.com>
Desc: Bug 911955 - Discard all non-SI/SL WAP Push messages r=vingtetun

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https://hg.mozilla.org/integration/gaia-central/rev/6b5afedf06ce
Author: GaryChen(pychen) <mmm198219@gmail.com>
Desc: Merge pull request #12084 from mpizza/Bug_914663_mozbrowserresize

Bug 891763 - Browser API: mozbrowserwindowresizeto and mozbrowserwindowr...
r=rudylu

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https://hg.mozilla.org/integration/gaia-central/rev/21ffb4f7ed39
Author: GaryChen(pychen) <mmm198219@gmail.com>
Desc: Bug 914663 - Browser API: mozbrowserwindowresizeto and mozbrowserwindowresizeby events
    add Browser API in keybaord manager and keyboard app, remove hack parts.

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "f90148fcad6ca9e48aebd94532387e0595ecb2ea", 
+    "revision": "bf3a8d594a557a0f9fd6425e8d05fe9610e222e4", 
     "repo_path": "/integration/gaia-central"
 }