Bumping gaia.json for 6 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/c09f78f6bdd9
Author: Gareth Aye <gaye@mozilla.com>
Desc: Merge pull request #12992 from gaye/bug-920261

Bug 920261 - mailto links broken r=jrburke

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https://hg.mozilla.org/integration/gaia-central/rev/5daf75353a52
Author: Gareth Aye <gaye@mozilla.com>
Desc: Bug 920261 - fix mailto links r=jrburke

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https://hg.mozilla.org/integration/gaia-central/rev/57e87158185f
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #13002 from cctuan/926871

Bug 926871 - Prevent reflowing when the software button is hidden and add test cases for software button manager

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https://hg.mozilla.org/integration/gaia-central/rev/3b52ff85884c
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 926871 - Prevent reflowing when the software button is hidden

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https://hg.mozilla.org/integration/gaia-central/rev/45d9ade0030c
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #13097 from dmarcos/bug928614

Bug 931054 - [Camera] filmstrip.js access undefined preview metadata

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https://hg.mozilla.org/integration/gaia-central/rev/412e5f78f422
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Bug 931054 - [Camera] filmstrip.js access undefined preview metadata
Bumping gaia.json for 1 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/dfae5ff6b7c4
Author: Corey Frang <gnarf37@gmail.com>
Desc: Bug 912010 - [Keyboard][V1.2] Default Keyboard when all keyboards are de-selected - r=rlu r=garychen r=arthurcc

- Refactors `KeyboardHelper`
  - Renames the application method to `getApps`, which now caches response until the apps change
  - Adds a new API `getLayouts` to get a callback with an array of layouts.
  - Adds a new API `watchLayouts` to get a callback whenever layout settings or apps change
  - No longer calls `saveToSettings` itself when changing layout parameters.  This allows a consumer to batch operations before saving.
  - New method `checkDefaults` will make sure there is at least one `text` `url` and `number` keyboard enabled, calling the callback with anything it enabled.
  - +unit test suite.

- ManifestHelper now automatically returns a ManifestHelper for each object it contains
  - +unit test suite
  - now waits until access time to handle the language selection instead of creation time
     - this allows holding the one manifest helper and having its "name" property change with the language

- Settings Changes
  - Now uses `watchLayouts` from keyboard_helper
  - Now calls `checkDefaults` when disabling a keyboard
    - If a default is enabled opens a DefaultKeyboardEnabledDialog
  - Removed a bunch of commented out code for dealing with the old layout settings

- System Changes
  - Now uses `watchLayouts` from keyboard_helper
  - Will call `checkDefaults` whenever it can't find a keyboard to show, showing the default from `text` if it still can't find one

- Test suite
  - Moved some mocks to shared and updated require statements
  - Mock Settings now allows a "sync mode" that can call the callbacks for observers on demand.

Closes gh-12866