Add MODIFY_AUDIO_SETTINGS permission in Android manifest and implementation in opensl.

Add MODIFY_AUDIO_SETTINGS permission in Android manifest and implementation in opensl.

MODIFY_AUDIO_SETTINGS allows application to be able to configure audio settings.

In opensl back end, a function SetAudioMode is added to set audio mode for webrtc.

BUG=180328

[leozwang1, 2013-03-05 06:14:16]

please take a look.

[Yaron, 2013-03-05 17:44:30]

On 2013/03/05 06:14:16, leozwang1 wrote:
> please take a look.

1. This needs an associated bug ID
2. How many more permissions are needed for WebRTC? Can we gather a list of all
permissions that will be needed?
3. Please reference in the CL description the specific APIs which require this
new permission.

[leozwang1, 2013-03-05 20:58:57]

This could could have been done in a more organized way, we're improving it.
Please see my answers inline.
 
> 1. This needs an associated bug ID
BUG=180328

> 2. How many more permissions are needed for WebRTC? Can we gather a list of
all permissions that will be needed?
In WebRTC, we have android.permission.WRITE_EXTERNAL_STORAGE, but it's more for
debugging. After adding MODIFY_AUDIO_SETTINGS flag, we don't need more flags in
near future.

> 3. Please reference in the CL description the specific APIs which require this
new permission.
Done.
please take a look.

[Yaron, 2013-03-06 03:10:39]

I'd prefer to wait until the other patch is ready to land. We should only add
permissions when we need them.