Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/377478a69651
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Revert "Revert "Bug 1042744 - Add a container around app iframes and some chrome UI. r=alive" under suspicion of breaking JB emulator builds""

This reverts commit a6d415335e8e73bf8bca00cd8591fd59164f915a.
Bumping manifests a=b2g-bump