Store device salt callback instead of resource context in WebRTC Audio Private API

Store device salt callback instead of resource context in WebRTC Audio Private API

The resource context pointer was used only to get access to the device
ID salt callback. However, the resource context pointer can become dangling and cause
use-after-free issues.

BUG=572224
Review URL: https://codereview.chromium.org/1692913003

Cr-Commit-Position: refs/heads/master@{#375259}
(cherry picked from commit c4e893a3352c34e1a22ec6afad115887a69f576e)

Committed: https://chromium.googlesource.com/chromium/src/+/048b308e940105b66e242ec9e0e2efe7d7adf0a4

[Guido Urdaneta, 2016-02-17 00:20:14]

Description was changed from

==========
Store device salt callback instead of resource context in WebRTC Audio Private
API

The resource context pointer was used only to get access to the device
ID salt callback. However, the resource context pointer can become dangling and
cause
use-after-free issues.

BUG=572224

Review URL: https://codereview.chromium.org/1692913003

Cr-Commit-Position: refs/heads/master@{#375259}
(cherry picked from commit c4e893a3352c34e1a22ec6afad115887a69f576e)
==========

to

==========
Store device salt callback instead of resource context in WebRTC Audio Private
API

The resource context pointer was used only to get access to the device
ID salt callback. However, the resource context pointer can become dangling and
cause
use-after-free issues.

BUG=572224

Review URL: https://codereview.chromium.org/1692913003

Cr-Commit-Position: refs/heads/master@{#375259}
(cherry picked from commit c4e893a3352c34e1a22ec6afad115887a69f576e)

Committed:
https://chromium.googlesource.com/chromium/src/+/048b308e940105b66e242ec9e0e2...
==========

[Guido Urdaneta, 2016-02-17 00:20:15]

Committed patchset #1 (id:1) manually as
048b308e940105b66e242ec9e0e2efe7d7adf0a4.