Revert of Implement HasInputDevices in CrasAudioManager

Revert of Implement HasInputDevices in CrasAudioManager (patchset #10 id:170001 of https://codereview.chromium.org/1186293003/)

Reason for revert:
Looks like this broke the build: http://build.chromium.org/p/chromium.chromiumos/buildstatus?builder=ChromiumOS%20amd64-generic%20Compile&number=1769

Original issue's description:
> Implement HasInputDevices in CrasAudioManager
>
> Currently in CrasAudioManager, HasInputDevices always returns True.
> We need to let HasInputDevices reflect the truth for device without
> internal microphone like ChromeBox.
> Let CrasAudioHandler updates the flag in CrasAudioManager whenever
> CrasAudioHandler gets the audio node info from Cras.
>
> Add a property is_for_simple_usage to AudioDeviceType to indicate
> that a device is for simple usage, not for special usage like
> loopback, always on keyword mic, or keyboard mic.
>
> This property can also replace the logic in audio_detailed_view.cc
> to filter out the devices that we do not want to display in UI.
>
> BUG=490851
> TEST=Check audio devices in UI does not contain loopback devices.
> TEST=Check virtual keyboard does not show microphone for chromebox
>      (Not tested yet).
>
> R=dalecurtis@chromium.org, derat@chromium.org, dgreid@chromium.org, jennyz@chromium.org
>
> Committed: https://crrev.com/3c3d910e31448a88e014b31334a57242ba5e8960
> Cr-Commit-Position: refs/heads/master@{#337791}

TBR=dalecurtis@chromium.org,derat@chromium.org,dgreid@chromium.org,jennyz@chromium.org,stevenjb@chromium.org,cychiang@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=490851
Committed: https://crrev.com/653d0be5f55495ff9abc57f97ab21565cbc3b860
Cr-Commit-Position: refs/heads/master@{#337798}

[Mattias Nissler (ping if slow), 2015-07-08 10:44:10]

Created Revert of Implement HasInputDevices in CrasAudioManager

[commit-bot: I haz the power, 2015-07-08 10:44:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1220873010/1

[commit-bot: I haz the power, 2015-07-08 10:44:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-08 10:45:57]

Patchset 1 (id:??) landed as
https://crrev.com/653d0be5f55495ff9abc57f97ab21565cbc3b860
Cr-Commit-Position: refs/heads/master@{#337798}