Revert "Removes deprecated ADM APIs."
Revert "Removes deprecated ADM APIs."

This reverts commit 1882d8509a138468c6dd8437506973d236c80e62.

Reason for revert: Broke the internal projects.

Original change's description:
> Removes deprecated ADM APIs.
> 
> Final stage since these APIs are no longer used in Chrome.
> 
> Bug: webrtc:7306
> Change-Id: Ia116671bc888daa75c4105ad1ebeb21833f5d090
> Reviewed-on: https://webrtc-review.googlesource.com/25220
> Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
> Commit-Queue: Henrik Andreassson <henrika@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#20836}

TBR=solenberg@webrtc.org,henrika@webrtc.org

Change-Id: If8dd4212fb3e8c6944643d3794f673837977bf4e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:7306
Reviewed-on: https://webrtc-review.googlesource.com/25320
Reviewed-by: Zhi Huang <64514bc03b49e67cfb75da60b665f8d8aefa50ca@webrtc.org>
Commit-Queue: Zhi Huang <64514bc03b49e67cfb75da60b665f8d8aefa50ca@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#20840}
TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc