Revert "Audio: make safe headset volume user configurable"

This reverts commit 6ffd4eb55bf74441ef7ae157664017c141d84ec7.
Disable safe headset volume warning

In some countries, regulations require that a warning be displayed
when the media volume is being raised above recommended level while
using a headset. As this is regulation we don't simply remove the
warning, but instead give the user the option to disable it.

In this implementation, the user is presented with the warning at
least once, at which point they are given the option to disable it
completely (via on-the-spot preference).

PS1: initial commit
PS2: update to reflect changes to https://gerrit.paranoidandroid.co/#/c/3702/
PS3: add new drawable (thanks Arz....finally)

Change-Id: Ib29ddb7f0ed5b1d45ed56d13bd6f7e14d005da79
VolumePanel: Fix Theme Engine support with On-The-Spot dialog

Our on the spot feature needs to write to system. Since VolumePanel when is
recreated uses theme engine context (and in this case is fked), pass to on the spot dialog always the
first system initialized one. Thanks to @David96 helping find this out :)

This way we lose theming for the safe headset on the spot dialog,
but we're already finding a really good fix, we have something already :)

Fix AOSPA-482

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: I492cd8e24b09d856d23697b84113664379703cf1
SettingConfirmationHelper: Create internal UiContext to load themed resources

As for Theme Engine introduction, we have to handle context changes. In this case,
a wrong context is passed from VolumePanel to SettingConfirmationHeHlper to be able
to write to system. We fixed it by sending a system context separately from VolumePanel
to let it write to system. Although, right now Safe Headset dialog isn't themed because it
doesn't receive the theme context.

Fix that by creating a new UiContext inside SettingConfirmationHelper, that we will use
just to load themed resources.

Continue this https://gerrit.paranoidandroid.co/#/c/4452/

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
SettingConfirmationHelper: Unbreak public api

Missing @hide for javadoc breaks public api.

Change-Id: I29c5e8b5b2ae5a998fdf84895808f79d1e7ae500
Signed-off-by: Evan Anderson <evan@thelinuxman.us>